21430441957 has 2 divisors, whose sum is σ = 21430441958. Its totient is φ = 21430441956.

The previous prime is 21430441897. The next prime is 21430441979. The reversal of 21430441957 is 75914403412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19368010561 + 2062431396 = 139169^2 + 45414^2 .

It is a cyclic number.

It is not a de Polignac number, because 21430441957 - 2¹¹ = 21430439909 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21430441657) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10715220978 + 10715220979.

It is an arithmetic number, because the mean of its divisors is an integer number (10715220979).

Almost surely, 2^21430441957 is an apocalyptic number.

It is an amenable number.

21430441957 is a deficient number, since it is larger than the sum of its proper divisors (1).

21430441957 is an equidigital number, since it uses as much as digits as its factorization.

21430441957 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 120960, while the sum is 40.

The spelling of 21430441957 in words is "twenty-one billion, four hundred thirty million, four hundred forty-one thousand, nine hundred fifty-seven".