21376287 has 12 divisors (see below), whose sum is σ = 31224960. Its totient is φ = 14090208.

The previous prime is 21376279. The next prime is 21376297. The reversal of 21376287 is 78267312.

21376287 is a `hidden beast` number, since 2 + 1 + 376 + 287 = 666.

It is not a de Polignac number, because 21376287 - 2³ = 21376279 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21376217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12543 + ... + 14144.

It is an arithmetic number, because the mean of its divisors is an integer number (2602080).

Almost surely, 2^21376287 is an apocalyptic number.

21376287 is a deficient number, since it is larger than the sum of its proper divisors (9848673).

21376287 is a wasteful number, since it uses less digits than its factorization.

21376287 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26782 (or 26779 counting only the distinct ones).

The product of its digits is 28224, while the sum is 36.

The square root of 21376287 is about 4623.4496861110. The cubic root of 21376287 is about 277.5305250083.

The spelling of 21376287 in words is "twenty-one million, three hundred seventy-six thousand, two hundred eighty-seven".