21648525188401 has 4 divisors (see below), whose sum is σ = 21650108970100. Its totient is φ = 21646941406704.

The previous prime is 21648525188399. The next prime is 21648525188471. The reversal of 21648525188401 is 10488152584612.

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 19077248798001 + 2571276390400 = 4367751^2 + 1603520^2 .

It is a cyclic number.

It is not a de Polignac number, because 21648525188401 - 2¹ = 21648525188399 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21648525188471) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 791870346 + ... + 791897683.

It is an arithmetic number, because the mean of its divisors is an integer number (5412527242525).

Almost surely, 2^{21648525188401} is an apocalyptic number.

It is an amenable number.

21648525188401 is a deficient number, since it is larger than the sum of its proper divisors (1583781699).

21648525188401 is a wasteful number, since it uses less digits than its factorization.

21648525188401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1583781698.

The product of its (nonzero) digits is 4915200, while the sum is 55.

The spelling of 21648525188401 in words is "twenty-one trillion, six hundred forty-eight billion, five hundred twenty-five million, one hundred eighty-eight thousand, four hundred one".