21415199957 has 2 divisors, whose sum is σ = 21415199958. Its totient is φ = 21415199956.

The previous prime is 21415199947. The next prime is 21415199987. The reversal of 21415199957 is 75999151412.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10724880721 + 10690319236 = 103561^2 + 103394^2 .

It is a cyclic number.

It is not a de Polignac number, because 21415199957 - 2⁴ = 21415199941 is a prime.

It is a super-2 number, since 2×21415199957² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21415199899 and 21415199908.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21415199917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10707599978 + 10707599979.

It is an arithmetic number, because the mean of its divisors is an integer number (10707599979).

Almost surely, 2^21415199957 is an apocalyptic number.

It is an amenable number.

21415199957 is a deficient number, since it is larger than the sum of its proper divisors (1).

21415199957 is an equidigital number, since it uses as much as digits as its factorization.

21415199957 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1020600, while the sum is 53.

The spelling of 21415199957 in words is "twenty-one billion, four hundred fifteen million, one hundred ninety-nine thousand, nine hundred fifty-seven".