20641625 has 8 divisors (see below), whose sum is σ = 25760904. Its totient is φ = 16513200.

The previous prime is 20641609. The next prime is 20641627. The reversal of 20641625 is 52614602.

It can be written as a sum of positive squares in 4 ways, for example, as 4609609 + 16032016 = 2147^2 + 4004^2 .

It is not a de Polignac number, because 20641625 - 2⁴ = 20641609 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 20641594 and 20641603.

It is not an unprimeable number, because it can be changed into a prime (20641627) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 82442 + ... + 82691.

It is an arithmetic number, because the mean of its divisors is an integer number (3220113).

Almost surely, 2^20641625 is an apocalyptic number.

20641625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

20641625 is a deficient number, since it is larger than the sum of its proper divisors (5119279).

20641625 is an equidigital number, since it uses as much as digits as its factorization.

20641625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165148 (or 165138 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 26.

The square root of 20641625 is about 4543.3055147106. The cubic root of 20641625 is about 274.3139926073.

The spelling of 20641625 in words is "twenty million, six hundred forty-one thousand, six hundred twenty-five".