21516304035757 has 6 divisors (see below), whose sum is σ = 21659739794574. Its totient is φ = 21373811933400.

The previous prime is 21516304035739. The next prime is 21516304035781. The reversal of 21516304035757 is 75753040361512.

It can be written as a sum of positive squares in only one way, i.e., 12125793448521 + 9390510587236 = 3482211^2 + 3064394^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21516304035757 is a prime.

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 21516304035757.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21516304035257) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 471805278 + ... + 471850879.

It is an arithmetic number, because the mean of its divisors is an integer number (3609956632429).

Almost surely, 2^{21516304035757} is an apocalyptic number.

It is an amenable number.

21516304035757 is a deficient number, since it is larger than the sum of its proper divisors (143435758817).

21516304035757 is an frugal number, since it uses more digits than its factorization.

21516304035757 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 943656459 (or 943656308 counting only the distinct ones).

The product of its (nonzero) digits is 2646000, while the sum is 49.

The spelling of 21516304035757 in words is "twenty-one trillion, five hundred sixteen billion, three hundred four million, thirty-five thousand, seven hundred fifty-seven".