16406981 has 4 divisors (see below), whose sum is σ = 17120352. Its totient is φ = 15693612.

The previous prime is 16406977. The next prime is 16406993. The reversal of 16406981 is 18960461.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 16406981 - 2² = 16406977 is a prime.

It is a super-2 number, since 2×16406981² = 538378051068722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16406941) 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, 356651 + ... + 356696.

It is an arithmetic number, because the mean of its divisors is an integer number (4280088).

Almost surely, 2^16406981 is an apocalyptic number.

It is an amenable number.

16406981 is a deficient number, since it is larger than the sum of its proper divisors (713371).

16406981 is an equidigital number, since it uses as much as digits as its factorization.

16406981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 713370.

The product of its (nonzero) digits is 10368, while the sum is 35.

The square root of 16406981 is about 4050.5531720988. The cubic root of 16406981 is about 254.1028630435.

The spelling of 16406981 in words is "sixteen million, four hundred six thousand, nine hundred eighty-one".