21531934969 has 2 divisors, whose sum is σ = 21531934970. Its totient is φ = 21531934968.

The previous prime is 21531934951. The next prime is 21531934979. The reversal of 21531934969 is 96943913512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14984697744 + 6547237225 = 122412^2 + 80915^2 .

It is a cyclic number.

It is not a de Polignac number, because 21531934969 - 2⁵ = 21531934937 is a prime.

It is a super-2 number, since 2×21531934969² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21531934979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10765967484 + 10765967485.

It is an arithmetic number, because the mean of its divisors is an integer number (10765967485).

Almost surely, 2^21531934969 is an apocalyptic number.

It is an amenable number.

21531934969 is a deficient number, since it is larger than the sum of its proper divisors (1).

21531934969 is an equidigital number, since it uses as much as digits as its factorization.

21531934969 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1574640, while the sum is 52.

The spelling of 21531934969 in words is "twenty-one billion, five hundred thirty-one million, nine hundred thirty-four thousand, nine hundred sixty-nine".