20961870 has 16 divisors (see below), whose sum is σ = 50308560. Its totient is φ = 5589824.

The previous prime is 20961851. The next prime is 20961881. The reversal of 20961870 is 7816902.

It is a congruent number.

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, 349335 + ... + 349394.

It is an arithmetic number, because the mean of its divisors is an integer number (3144285).

Almost surely, 2^20961870 is an apocalyptic number.

20961870 is an abundant number, since it is smaller than the sum of its proper divisors (29346690).

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

20961870 is a wasteful number, since it uses less digits than its factorization.

20961870 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 698739.

The product of its (nonzero) digits is 6048, while the sum is 33.

The square root of 20961870 is about 4578.4134806721. The cubic root of 20961870 is about 275.7253358717.

The spelling of 20961870 in words is "twenty million, nine hundred sixty-one thousand, eight hundred seventy".