20725531 has 4 divisors (see below), whose sum is σ = 20779200. Its totient is φ = 20671864.

The previous prime is 20725501. The next prime is 20725547. The reversal of 20725531 is 13552702.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13552702 = 2 ⋅6776351.

It is a cyclic number.

It is not a de Polignac number, because 20725531 - 2⁷ = 20725403 is a prime.

It is a super-2 number, since 2×20725531² = 859095270463922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20725496 and 20725505.

It is not an unprimeable number, because it can be changed into a prime (20725501) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26251 + ... + 27028.

It is an arithmetic number, because the mean of its divisors is an integer number (5194800).

Almost surely, 2^20725531 is an apocalyptic number.

20725531 is a deficient number, since it is larger than the sum of its proper divisors (53669).

20725531 is an equidigital number, since it uses as much as digits as its factorization.

20725531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53668.

The product of its (nonzero) digits is 2100, while the sum is 25.

The square root of 20725531 is about 4552.5301756276. The cubic root of 20725531 is about 274.6851758102.

The spelling of 20725531 in words is "twenty million, seven hundred twenty-five thousand, five hundred thirty-one".