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16120981 = 17948293
BaseRepresentation
bin111101011111…
…110010010101
31010100000211101
4331133302111
513111332411
61333310101
7254011642
oct75376225
933300741
1016120981
119110a28
125495331
133455956
1421d8dc9
1516368c1
hexf5fc95

16120981 has 4 divisors (see below), whose sum is σ = 17069292. Its totient is φ = 15172672.

The previous prime is 16120967. The next prime is 16121029. The reversal of 16120981 is 18902161.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18902161 = 144713063.

It can be written as a sum of positive squares in 2 ways, for example, as 10504081 + 5616900 = 3241^2 + 2370^2 .

It is a cyclic number.

It is not a de Polignac number, because 16120981 - 211 = 16118933 is a prime.

It is a super-4 number, since 4×161209814 (a number of 30 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16120921) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 474130 + ... + 474163.

It is an arithmetic number, because the mean of its divisors is an integer number (4267323).

Almost surely, 216120981 is an apocalyptic number.

It is an amenable number.

16120981 is a deficient number, since it is larger than the sum of its proper divisors (948311).

16120981 is an equidigital number, since it uses as much as digits as its factorization.

16120981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 948310.

The product of its (nonzero) digits is 864, while the sum is 28.

The square root of 16120981 is about 4015.0941458452. The cubic root of 16120981 is about 252.6177263656.

The spelling of 16120981 in words is "sixteen million, one hundred twenty thousand, nine hundred eighty-one".

Divisors: 1 17 948293 16120981