21494239865 has 16 divisors (see below), whose sum is σ = 30494292480. Its totient is φ = 14230668480.

The previous prime is 21494239859. The next prime is 21494239903. The reversal of 21494239865 is 56893249412.

It is not a de Polignac number, because 21494239865 - 2¹⁰ = 21494238841 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10587281 + ... + 10589310.

It is an arithmetic number, because the mean of its divisors is an integer number (1905893280).

Almost surely, 2^21494239865 is an apocalyptic number.

It is an amenable number.

21494239865 is a deficient number, since it is larger than the sum of its proper divisors (9000052615).

21494239865 is a wasteful number, since it uses less digits than its factorization.

21494239865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21176632.

The product of its digits is 3732480, while the sum is 53.

The spelling of 21494239865 in words is "twenty-one billion, four hundred ninety-four million, two hundred thirty-nine thousand, eight hundred sixty-five".