20556490 has 8 divisors (see below), whose sum is σ = 37001700. Its totient is φ = 8222592.

The previous prime is 20556479. The next prime is 20556491. The reversal of 20556490 is 9465502.

It can be written as a sum of positive squares in 2 ways, for example, as 17497489 + 3059001 = 4183^2 + 1749^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×20556490² = 845138562240200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20556491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1027815 + ... + 1027834.

Almost surely, 2^20556490 is an apocalyptic number.

20556490 is a deficient number, since it is larger than the sum of its proper divisors (16445210).

20556490 is a wasteful number, since it uses less digits than its factorization.

20556490 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2055656.

The product of its (nonzero) digits is 10800, while the sum is 31.

The square root of 20556490 is about 4533.9265543235. The cubic root of 20556490 is about 273.9363430361.

The spelling of 20556490 in words is "twenty million, five hundred fifty-six thousand, four hundred ninety".