20490556 has 6 divisors (see below), whose sum is σ = 35858480. Its totient is φ = 10245276.

The previous prime is 20490551. The next prime is 20490557. The reversal of 20490556 is 65509402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20490551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2561316 + ... + 2561323.

Almost surely, 2^20490556 is an apocalyptic number.

It is an amenable number.

20490556 is a deficient number, since it is larger than the sum of its proper divisors (15367924).

20490556 is a wasteful number, since it uses less digits than its factorization.

20490556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5122643 (or 5122641 counting only the distinct ones).

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

The square root of 20490556 is about 4526.6495335955. The cubic root of 20490556 is about 273.6431499207.

Adding to 20490556 its reverse (65509402), we get a palindrome (85999958).

The spelling of 20490556 in words is "twenty million, four hundred ninety thousand, five hundred fifty-six".