20642156 has 24 divisors (see below), whose sum is σ = 37914240. Its totient is φ = 9820800.

The previous prime is 20642129. The next prime is 20642161. The reversal of 20642156 is 65124602.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6200 + ... + 8928.

It is an arithmetic number, because the mean of its divisors is an integer number (1579760).

Almost surely, 2^20642156 is an apocalyptic number.

It is an amenable number.

20642156 is a deficient number, since it is larger than the sum of its proper divisors (17272084).

20642156 is a wasteful number, since it uses less digits than its factorization.

20642156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2825 (or 2823 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 26.

The square root of 20642156 is about 4543.3639519633. The cubic root of 20642156 is about 274.3163448039.

Adding to 20642156 its reverse (65124602), we get a palindrome (85766758).

The spelling of 20642156 in words is "twenty million, six hundred forty-two thousand, one hundred fifty-six".