21432313021 has 16 divisors (see below), whose sum is σ = 24631849984. Its totient is φ = 18267410304.

The previous prime is 21432313003. The next prime is 21432313043. The reversal of 21432313021 is 12031323412.

It is a cyclic number.

It is not a de Polignac number, because 21432313021 - 2¹⁵ = 21432280253 is a prime.

It is a super-2 number, since 2×21432313021² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21432312983 and 21432313001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21432313051) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1455331 + ... + 1469983.

It is an arithmetic number, because the mean of its divisors is an integer number (1539490624).

Almost surely, 2^21432313021 is an apocalyptic number.

It is an amenable number.

21432313021 is a deficient number, since it is larger than the sum of its proper divisors (3199536963).

21432313021 is a wasteful number, since it uses less digits than its factorization.

21432313021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15820.

The product of its (nonzero) digits is 864, while the sum is 22.

Adding to 21432313021 its reverse (12031323412), we get a palindrome (33463636433).

The spelling of 21432313021 in words is "twenty-one billion, four hundred thirty-two million, three hundred thirteen thousand, twenty-one".