21035501957 has 2 divisors, whose sum is σ = 21035501958. Its totient is φ = 21035501956.

The previous prime is 21035501951. The next prime is 21035501969. The reversal of 21035501957 is 75910553012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19110574081 + 1924927876 = 138241^2 + 43874^2 .

It is a cyclic number.

It is not a de Polignac number, because 21035501957 - 2³⁴ = 3855632773 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21035501957.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21035501951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10517750978 + 10517750979.

It is an arithmetic number, because the mean of its divisors is an integer number (10517750979).

Almost surely, 2^21035501957 is an apocalyptic number.

It is an amenable number.

21035501957 is a deficient number, since it is larger than the sum of its proper divisors (1).

21035501957 is an equidigital number, since it uses as much as digits as its factorization.

21035501957 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 47250, while the sum is 38.

The spelling of 21035501957 in words is "twenty-one billion, thirty-five million, five hundred one thousand, nine hundred fifty-seven".