20990770 has 16 divisors (see below), whose sum is σ = 38705688. Its totient is φ = 8191360.

The previous prime is 20990759. The next prime is 20990773. The reversal of 20990770 is 7709902.

It can be written as a sum of positive squares in 4 ways, for example, as 17783089 + 3207681 = 4217^2 + 1791^2 .

It is a super-2 number, since 2×20990770² = 881224850385800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20990773) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25189 + ... + 26008.

Almost surely, 2^20990770 is an apocalyptic number.

20990770 is a deficient number, since it is larger than the sum of its proper divisors (17714918).

20990770 is a wasteful number, since it uses less digits than its factorization.

20990770 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51245.

The product of its (nonzero) digits is 7938, while the sum is 34.

The square root of 20990770 is about 4581.5685087097. The cubic root of 20990770 is about 275.8519912859.

The spelling of 20990770 in words is "twenty million, nine hundred ninety thousand, seven hundred seventy".