21054999987 has 48 divisors (see below), whose sum is σ = 36843049152. Its totient is φ = 11311073280.

The previous prime is 21054999983. The next prime is 21054999989. The reversal of 21054999987 is 78999945012.

21054999987 is a `hidden beast` number, since 2 + 1 + 0 + 549 + 9 + 9 + 9 + 87 = 666.

It is not a de Polignac number, because 21054999987 - 2² = 21054999983 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (21054999983) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 993037 + ... + 1014017.

It is an arithmetic number, because the mean of its divisors is an integer number (767563524).

Almost surely, 2^21054999987 is an apocalyptic number.

21054999987 is a deficient number, since it is larger than the sum of its proper divisors (15788049165).

21054999987 is a wasteful number, since it uses less digits than its factorization.

21054999987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21948 (or 21945 counting only the distinct ones).

The product of its (nonzero) digits is 14696640, while the sum is 63.

The spelling of 21054999987 in words is "twenty-one billion, fifty-four million, nine hundred ninety-nine thousand, nine hundred eighty-seven".