21985356431 has 8 divisors (see below), whose sum is σ = 22761292800. Its totient is φ = 21210608160.

The previous prime is 21985356409. The next prime is 21985356443. The reversal of 21985356431 is 13465358912.

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 21985356431 - 2²⁶ = 21918247567 is a prime.

It is a super-2 number, since 2×21985356431² (a number of 21 digits) 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 (21981356431) 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, 259280 + ... + 333461.

It is an arithmetic number, because the mean of its divisors is an integer number (2845161600).

Almost surely, 2^21985356431 is an apocalyptic number.

21985356431 is a deficient number, since it is larger than the sum of its proper divisors (775936369).

21985356431 is a wasteful number, since it uses less digits than its factorization.

21985356431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 594049.

The product of its digits is 777600, while the sum is 47.

The spelling of 21985356431 in words is "twenty-one billion, nine hundred eighty-five million, three hundred fifty-six thousand, four hundred thirty-one".