21431032021 has 4 divisors (see below), whose sum is σ = 24492608032. Its totient is φ = 18369456012.

The previous prime is 21431032019. The next prime is 21431032037. The reversal of 21431032021 is 12023013412.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21431032021 - 2¹ = 21431032019 is a prime.

It is a super-3 number, since 3×21431032021³ (a number of 32 digits) contains 333 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 21431032021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21431032321) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1530787995 + ... + 1530788008.

It is an arithmetic number, because the mean of its divisors is an integer number (6123152008).

Almost surely, 2^21431032021 is an apocalyptic number.

It is an amenable number.

21431032021 is a deficient number, since it is larger than the sum of its proper divisors (3061576011).

21431032021 is an equidigital number, since it uses as much as digits as its factorization.

21431032021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3061576010.

The product of its (nonzero) digits is 288, while the sum is 19.

Adding to 21431032021 its reverse (12023013412), we get a palindrome (33454045433).

The spelling of 21431032021 in words is "twenty-one billion, four hundred thirty-one million, thirty-two thousand, twenty-one".