20021688 has 32 divisors (see below), whose sum is σ = 55616400. Its totient is φ = 6673824.

The previous prime is 20021669. The next prime is 20021689. The reversal of 20021688 is 88612002.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021689) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 46131 + ... + 46562.

Almost surely, 2^20021688 is an apocalyptic number.

It is an amenable number.

20021688 is an abundant number, since it is smaller than the sum of its proper divisors (35594712).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20021688 is a wasteful number, since it uses less digits than its factorization.

20021688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92708 (or 92698 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 20021688 is about 4474.5600901094. The cubic root of 20021688 is about 271.5398433635.

The spelling of 20021688 in words is "twenty million, twenty-one thousand, six hundred eighty-eight".