20990525 has 6 divisors (see below), whose sum is σ = 26028282. Its totient is φ = 16792400.

The previous prime is 20990521. The next prime is 20990539. The reversal of 20990525 is 52509902.

It can be written as a sum of positive squares in 3 ways, for example, as 6160324 + 14830201 = 2482^2 + 3851^2 .

It is not a de Polignac number, because 20990525 - 2² = 20990521 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20990491 and 20990500.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20990521) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 419786 + ... + 419835.

It is an arithmetic number, because the mean of its divisors is an integer number (4338047).

Almost surely, 2^20990525 is an apocalyptic number.

20990525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

20990525 is a deficient number, since it is larger than the sum of its proper divisors (5037757).

20990525 is an equidigital number, since it uses as much as digits as its factorization.

20990525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 839631 (or 839626 counting only the distinct ones).

The product of its (nonzero) digits is 8100, while the sum is 32.

The square root of 20990525 is about 4581.5417710635. The cubic root of 20990525 is about 275.8509180523.

The spelling of 20990525 in words is "twenty million, nine hundred ninety thousand, five hundred twenty-five".