21357560137 has 4 divisors (see below), whose sum is σ = 21358520596. Its totient is φ = 21356599680.

The previous prime is 21357560057. The next prime is 21357560183. The reversal of 21357560137 is 73106575312.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12947936521 + 8409623616 = 113789^2 + 91704^2 .

It is a cyclic number.

It is not a de Polignac number, because 21357560137 - 2²⁷ = 21223342409 is a prime.

It is a super-2 number, since 2×21357560137² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21357560137.

It is not an unprimeable number, because it can be changed into a prime (21357563137) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 446064 + ... + 491617.

It is an arithmetic number, because the mean of its divisors is an integer number (5339630149).

Almost surely, 2^21357560137 is an apocalyptic number.

It is an amenable number.

21357560137 is a deficient number, since it is larger than the sum of its proper divisors (960459).

21357560137 is an equidigital number, since it uses as much as digits as its factorization.

21357560137 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 960458.

The product of its (nonzero) digits is 132300, while the sum is 40.

The spelling of 21357560137 in words is "twenty-one billion, three hundred fifty-seven million, five hundred sixty thousand, one hundred thirty-seven".