21430397533 has 4 divisors (see below), whose sum is σ = 21455521948. Its totient is φ = 21405273120.

The previous prime is 21430397477. The next prime is 21430397539. The reversal of 21430397533 is 33579303412.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10071527449 + 11358870084 = 100357^2 + 106578^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21430397533 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21430397539) 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, 12560928 + ... + 12562633.

It is an arithmetic number, because the mean of its divisors is an integer number (5363880487).

Almost surely, 2^21430397533 is an apocalyptic number.

It is an amenable number.

21430397533 is a deficient number, since it is larger than the sum of its proper divisors (25124415).

21430397533 is an equidigital number, since it uses as much as digits as its factorization.

21430397533 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25124414.

The product of its (nonzero) digits is 204120, while the sum is 40.

The spelling of 21430397533 in words is "twenty-one billion, four hundred thirty million, three hundred ninety-seven thousand, five hundred thirty-three".