21993523431 has 8 divisors (see below), whose sum is σ = 31990579584. Its totient is φ = 13329408120.

The previous prime is 21993523421. The next prime is 21993523457. The reversal of 21993523431 is 13432539912.

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

It is not a de Polignac number, because 21993523431 - 2¹⁰ = 21993522407 is a prime.

It is a super-2 number, since 2×21993523431² (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 (21993523421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 333235171 + ... + 333235236.

It is an arithmetic number, because the mean of its divisors is an integer number (3998822448).

Almost surely, 2^21993523431 is an apocalyptic number.

21993523431 is a deficient number, since it is larger than the sum of its proper divisors (9997056153).

21993523431 is a wasteful number, since it uses less digits than its factorization.

21993523431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 666470421.

The product of its digits is 174960, while the sum is 42.

The spelling of 21993523431 in words is "twenty-one billion, nine hundred ninety-three million, five hundred twenty-three thousand, four hundred thirty-one".