21540486987 has 6 divisors (see below), whose sum is σ = 31114036772. Its totient is φ = 14360324652.

The previous prime is 21540486959. The next prime is 21540486997. The reversal of 21540486987 is 78968404512.

It is a happy number.

21540486987 is a `hidden beast` number, since 2 + 1 + 540 + 4 + 8 + 6 + 98 + 7 = 666.

It is not a de Polignac number, because 21540486987 - 2⁷ = 21540486859 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21540486917) 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, 1196693713 + ... + 1196693730.

Almost surely, 2^21540486987 is an apocalyptic number.

21540486987 is a deficient number, since it is larger than the sum of its proper divisors (9573549785).

21540486987 is a wasteful number, since it uses less digits than its factorization.

21540486987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2393387449 (or 2393387446 counting only the distinct ones).

The product of its (nonzero) digits is 3870720, while the sum is 54.

The spelling of 21540486987 in words is "twenty-one billion, five hundred forty million, four hundred eighty-six thousand, nine hundred eighty-seven".