20687975 has 36 divisors (see below), whose sum is σ = 32258352. Its totient is φ = 12883200.

The previous prime is 20687969. The next prime is 20687977. The reversal of 20687975 is 57978602.

20687975 = 26³ + 27³ + ... + 95³.

It is not a de Polignac number, because 20687975 - 2¹² = 20683879 is a prime.

It is a Smith number, since the sum of its digits (44) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20687977) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 20687 + ... + 21663.

Almost surely, 2^20687975 is an apocalyptic number.

20687975 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

20687975 is a deficient number, since it is larger than the sum of its proper divisors (11570377).

20687975 is a wasteful number, since it uses less digits than its factorization.

20687975 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1016 (or 1000 counting only the distinct ones).

The product of its (nonzero) digits is 211680, while the sum is 44.

The square root of 20687975 is about 4548.4035660878. The cubic root of 20687975 is about 274.5191597360.

The spelling of 20687975 in words is "twenty million, six hundred eighty-seven thousand, nine hundred seventy-five".