21371907285 has 12 divisors (see below), whose sum is σ = 37044639372. Its totient is φ = 11398350528.

The previous prime is 21371907247. The next prime is 21371907371. The reversal of 21371907285 is 58270917312.

21371907285 is a `hidden beast` number, since 213 + 71 + 90 + 7 + 285 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 3606482916 + 17765424369 = 60054^2 + 133287^2 .

It is not a de Polignac number, because 21371907285 - 2⁷ = 21371907157 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 474931273 = 21371907285 / (2 + 1 + 3 + 7 + 1 + 9 + 0 + 7 + 2 + 8 + 5).

It is a self number, because there is not a number n which added to its sum of digits gives 21371907285.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 237465592 + ... + 237465681.

It is an arithmetic number, because the mean of its divisors is an integer number (3087053281).

Almost surely, 2^21371907285 is an apocalyptic number.

It is an amenable number.

21371907285 is a deficient number, since it is larger than the sum of its proper divisors (15672732087).

21371907285 is a wasteful number, since it uses less digits than its factorization.

21371907285 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 474931284 (or 474931281 counting only the distinct ones).

The product of its (nonzero) digits is 211680, while the sum is 45.

The spelling of 21371907285 in words is "twenty-one billion, three hundred seventy-one million, nine hundred seven thousand, two hundred eighty-five".