21085332981 has 8 divisors (see below), whose sum is σ = 28115437920. Its totient is φ = 14056058352.

The previous prime is 21085332911. The next prime is 21085333001. The reversal of 21085332981 is 18923358012.

It is a happy number.

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

It is not a de Polignac number, because 21085332981 - 2⁹ = 21085332469 is a prime.

It is a super-2 number, since 2×21085332981² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21085332911) 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, 145686 + ... + 251783.

It is an arithmetic number, because the mean of its divisors is an integer number (3514429740).

Almost surely, 2^21085332981 is an apocalyptic number.

It is an amenable number.

21085332981 is a deficient number, since it is larger than the sum of its proper divisors (7030104939).

21085332981 is a wasteful number, since it uses less digits than its factorization.

21085332981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 415155.

The product of its (nonzero) digits is 103680, while the sum is 42.

The spelling of 21085332981 in words is "twenty-one billion, eighty-five million, three hundred thirty-two thousand, nine hundred eighty-one".