21165603431 has 8 divisors (see below), whose sum is σ = 24969560064. Its totient is φ = 17556721560.

The previous prime is 21165603401. The next prime is 21165603439. The reversal of 21165603431 is 13430656112.

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

It is a de Polignac number, because none of the positive numbers 2^k-21165603431 is a prime.

It is a super-2 number, since 2×21165603431² (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 (21165603439) 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, 48768455 + ... + 48768888.

It is an arithmetic number, because the mean of its divisors is an integer number (3121195008).

Almost surely, 2^21165603431 is an apocalyptic number.

21165603431 is a deficient number, since it is larger than the sum of its proper divisors (3803956633).

21165603431 is an equidigital number, since it uses as much as digits as its factorization.

21165603431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97537381.

The product of its (nonzero) digits is 12960, while the sum is 32.

The spelling of 21165603431 in words is "twenty-one billion, one hundred sixty-five million, six hundred three thousand, four hundred thirty-one".