21507535701764 has 18 divisors (see below), whose sum is σ = 43783197678990. Its totient is φ = 9217515300672.

The previous prime is 21507535701749. The next prime is 21507535701767. The reversal of 21507535701764 is 46710753570512.

It can be written as a sum of positive squares in only one way, i.e., 12044578480900 + 9462957220864 = 3470530^2 + 3076192^2 .

It is not an unprimeable number, because it can be changed into a prime (21507535701767) 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, 54866162309 + ... + 54866162700.

It is an arithmetic number, because the mean of its divisors is an integer number (2432399871055).

Almost surely, 2^{21507535701764} is an apocalyptic number.

It is an amenable number.

21507535701764 is an abundant number, since it is smaller than the sum of its proper divisors (22275661977226).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21507535701764 is a wasteful number, since it uses less digits than its factorization.

21507535701764 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109732325027 (or 109732325018 counting only the distinct ones).

The product of its (nonzero) digits is 6174000, while the sum is 53.

The spelling of 21507535701764 in words is "twenty-one trillion, five hundred seven billion, five hundred thirty-five million, seven hundred one thousand, seven hundred sixty-four".