20879820 has 72 divisors (see below), whose sum is σ = 68215056. Its totient is φ = 5139072.

The previous prime is 20879819. The next prime is 20879821. The reversal of 20879820 is 2897802.

It is an interprime number because it is at equal distance from previous prime (20879819) and next prime (20879821).

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (20879821) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2122 + ... + 6801.

Almost surely, 2^20879820 is an apocalyptic number.

20879820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20879820 is an abundant number, since it is smaller than the sum of its proper divisors (47335236).

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

20879820 is a wasteful number, since it uses less digits than its factorization.

20879820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8951 (or 8946 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 36.

The square root of 20879820 is about 4569.4441675110. Note that the first 3 decimals coincide. The cubic root of 20879820 is about 275.3651128275.

The spelling of 20879820 in words is "twenty million, eight hundred seventy-nine thousand, eight hundred twenty".