20891370 has 16 divisors (see below), whose sum is σ = 50139360. Its totient is φ = 5571024.

The previous prime is 20891333. The next prime is 20891401. The reversal of 20891370 is 7319802.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30), and also a Moran number because the ratio is a prime number: 696379 = 20891370 / (2 + 0 + 8 + 9 + 1 + 3 + 7 + 0).

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, 348160 + ... + 348219.

It is an arithmetic number, because the mean of its divisors is an integer number (3133710).

Almost surely, 2^20891370 is an apocalyptic number.

20891370 is an abundant number, since it is smaller than the sum of its proper divisors (29247990).

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

20891370 is a wasteful number, since it uses less digits than its factorization.

20891370 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 696389.

The product of its (nonzero) digits is 3024, while the sum is 30.

The square root of 20891370 is about 4570.7078226463. The cubic root of 20891370 is about 275.4158776456.

The spelling of 20891370 in words is "twenty million, eight hundred ninety-one thousand, three hundred seventy".