21512926081 has 8 divisors (see below), whose sum is σ = 21587438880. Its totient is φ = 21438524448.

The previous prime is 21512926079. The next prime is 21512926087. The reversal of 21512926081 is 18062921512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21512926081 - 2¹ = 21512926079 is a prime.

It is a super-2 number, since 2×21512926081² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21512926081.

It is not an unprimeable number, because it can be changed into a prime (21512926087) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 369685 + ... + 423901.

It is an arithmetic number, because the mean of its divisors is an integer number (2698429860).

Almost surely, 2^21512926081 is an apocalyptic number.

It is an amenable number.

21512926081 is a deficient number, since it is larger than the sum of its proper divisors (74512799).

21512926081 is an equidigital number, since it uses as much as digits as its factorization.

21512926081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55583.

The product of its (nonzero) digits is 17280, while the sum is 37.

The spelling of 21512926081 in words is "twenty-one billion, five hundred twelve million, nine hundred twenty-six thousand, eighty-one".