20891490 has 32 divisors (see below), whose sum is σ = 50633856. Its totient is φ = 5516160.

The previous prime is 20891473. The next prime is 20891503. The reversal of 20891490 is 9419802.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 291 + ... + 6470.

It is an arithmetic number, because the mean of its divisors is an integer number (1582308).

Almost surely, 2^20891490 is an apocalyptic number.

20891490 is an abundant number, since it is smaller than the sum of its proper divisors (29742366).

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

20891490 is a wasteful number, since it uses less digits than its factorization.

20891490 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6874.

The product of its (nonzero) digits is 5184, while the sum is 33.

The square root of 20891490 is about 4570.7209496971. The cubic root of 20891490 is about 275.4164049741.

The spelling of 20891490 in words is "twenty million, eight hundred ninety-one thousand, four hundred ninety".