20685090 has 32 divisors (see below), whose sum is σ = 52565760. Its totient is φ = 5191424.

The previous prime is 20685089. The next prime is 20685101. The reversal of 20685090 is 9058602.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19770 + ... + 20789.

It is an arithmetic number, because the mean of its divisors is an integer number (1642680).

Almost surely, 2^20685090 is an apocalyptic number.

20685090 is an abundant number, since it is smaller than the sum of its proper divisors (31880670).

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

20685090 is a wasteful number, since it uses less digits than its factorization.

20685090 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40586.

The product of its (nonzero) digits is 4320, while the sum is 30.

The square root of 20685090 is about 4548.0864107886. The cubic root of 20685090 is about 274.5063983034.

The spelling of 20685090 in words is "twenty million, six hundred eighty-five thousand, ninety".