20139428 has 12 divisors (see below), whose sum is σ = 35290332. Its totient is φ = 10056480.

The previous prime is 20139409. The next prime is 20139443. The reversal of 20139428 is 82493102.

It can be written as a sum of positive squares in 2 ways, for example, as 13778944 + 6360484 = 3712^2 + 2522^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 20139428.

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, 638 + ... + 6378.

It is an arithmetic number, because the mean of its divisors is an integer number (2940861).

Almost surely, 2^20139428 is an apocalyptic number.

It is an amenable number.

20139428 is a deficient number, since it is larger than the sum of its proper divisors (15150904).

20139428 is a wasteful number, since it uses less digits than its factorization.

20139428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6622 (or 6620 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 20139428 is about 4487.6974051288. The cubic root of 20139428 is about 272.0710778779.

The spelling of 20139428 in words is "twenty million, one hundred thirty-nine thousand, four hundred twenty-eight".