21524239969 has 2 divisors, whose sum is σ = 21524239970. Its totient is φ = 21524239968.

The previous prime is 21524239963. The next prime is 21524240011. The reversal of 21524239969 is 96993242512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17480806225 + 4043433744 = 132215^2 + 63588^2 .

It is a cyclic number.

It is not a de Polignac number, because 21524239969 - 2¹¹ = 21524237921 is a prime.

It is a super-2 number, since 2×21524239969² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21524239963) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10762119984 + 10762119985.

It is an arithmetic number, because the mean of its divisors is an integer number (10762119985).

Almost surely, 2^21524239969 is an apocalyptic number.

It is an amenable number.

21524239969 is a deficient number, since it is larger than the sum of its proper divisors (1).

21524239969 is an equidigital number, since it uses as much as digits as its factorization.

21524239969 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2099520, while the sum is 52.

The spelling of 21524239969 in words is "twenty-one billion, five hundred twenty-four million, two hundred thirty-nine thousand, nine hundred sixty-nine".