21536857530772 has 6 divisors (see below), whose sum is σ = 37689500678858. Its totient is φ = 10768428765384.

The previous prime is 21536857530761. The next prime is 21536857530779. The reversal of 21536857530772 is 27703575863512.

It can be written as a sum of positive squares in only one way, i.e., 18819753654276 + 2717103876496 = 4338174^2 + 1648364^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21536857530772.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21536857530779) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2692107191343 + ... + 2692107191350.

Almost surely, 2^{21536857530772} is an apocalyptic number.

It is an amenable number.

21536857530772 is a deficient number, since it is larger than the sum of its proper divisors (16152643148086).

21536857530772 is a wasteful number, since it uses less digits than its factorization.

21536857530772 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5384214382697 (or 5384214382695 counting only the distinct ones).

The product of its (nonzero) digits is 74088000, while the sum is 61.

The spelling of 21536857530772 in words is "twenty-one trillion, five hundred thirty-six billion, eight hundred fifty-seven million, five hundred thirty thousand, seven hundred seventy-two".