21894570215 has 32 divisors (see below), whose sum is σ = 31809075840. Its totient is φ = 14123188224.

The previous prime is 21894570161. The next prime is 21894570227. The reversal of 21894570215 is 51207549812.

It is a cyclic number.

It is not a de Polignac number, because 21894570215 - 2¹⁸ = 21894308071 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1344341 + ... + 1360529.

It is an arithmetic number, because the mean of its divisors is an integer number (994033620).

Almost surely, 2^21894570215 is an apocalyptic number.

21894570215 is a deficient number, since it is larger than the sum of its proper divisors (9914505625).

21894570215 is a wasteful number, since it uses less digits than its factorization.

21894570215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18491.

The product of its (nonzero) digits is 201600, while the sum is 44.

The spelling of 21894570215 in words is "twenty-one billion, eight hundred ninety-four million, five hundred seventy thousand, two hundred fifteen".