20990356 has 6 divisors (see below), whose sum is σ = 36733130. Its totient is φ = 10495176.

The previous prime is 20990353. The next prime is 20990399. The reversal of 20990356 is 65309902.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 15085456 + 5904900 = 3884^2 + 2430^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20990353) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2623791 + ... + 2623798.

Almost surely, 2^20990356 is an apocalyptic number.

It is an amenable number.

20990356 is a deficient number, since it is larger than the sum of its proper divisors (15742774).

20990356 is a wasteful number, since it uses less digits than its factorization.

20990356 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5247593 (or 5247591 counting only the distinct ones).

The product of its (nonzero) digits is 14580, while the sum is 34.

The square root of 20990356 is about 4581.5233274534. The cubic root of 20990356 is about 275.8501777353.

The spelling of 20990356 in words is "twenty million, nine hundred ninety thousand, three hundred fifty-six".