20687644 has 12 divisors (see below), whose sum is σ = 37045624. Its totient is φ = 10103184.

The previous prime is 20687627. The next prime is 20687659. The reversal of 20687644 is 44678602.

It is a super-2 number, since 2×20687644² = 855957228541472, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 59967 + ... + 60310.

Almost surely, 2^20687644 is an apocalyptic number.

It is an amenable number.

20687644 is a deficient number, since it is larger than the sum of its proper divisors (16357980).

20687644 is a wasteful number, since it uses less digits than its factorization.

20687644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120324 (or 120322 counting only the distinct ones).

The product of its (nonzero) digits is 64512, while the sum is 37.

The square root of 20687644 is about 4548.3671795492. The cubic root of 20687644 is about 274.5176956596.

The spelling of 20687644 in words is "twenty million, six hundred eighty-seven thousand, six hundred forty-four".