20663525 has 6 divisors (see below), whose sum is σ = 25622802. Its totient is φ = 16530800.

The previous prime is 20663509. The next prime is 20663543. The reversal of 20663525 is 52536602.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 1012036 + 19651489 = 1006^2 + 4433^2 .

It is not a de Polignac number, because 20663525 - 2⁴ = 20663509 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 413246 + ... + 413295.

It is an arithmetic number, because the mean of its divisors is an integer number (4270467).

Almost surely, 2^20663525 is an apocalyptic number.

20663525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

20663525 is a deficient number, since it is larger than the sum of its proper divisors (4959277).

20663525 is an equidigital number, since it uses as much as digits as its factorization.

20663525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 826551 (or 826546 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 29.

The square root of 20663525 is about 4545.7150152644. The cubic root of 20663525 is about 274.4109706491.

The spelling of 20663525 in words is "twenty million, six hundred sixty-three thousand, five hundred twenty-five".