20531865 has 8 divisors (see below), whose sum is σ = 32851008. Its totient is φ = 10950320.

The previous prime is 20531839. The next prime is 20531867. The reversal of 20531865 is 56813502.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20531865 - 2⁹ = 20531353 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20531867) 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, 684381 + ... + 684410.

It is an arithmetic number, because the mean of its divisors is an integer number (4106376).

Almost surely, 2^20531865 is an apocalyptic number.

It is an amenable number.

20531865 is a deficient number, since it is larger than the sum of its proper divisors (12319143).

20531865 is a wasteful number, since it uses less digits than its factorization.

20531865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1368799.

The product of its (nonzero) digits is 7200, while the sum is 30.

The square root of 20531865 is about 4531.2101032726. The cubic root of 20531865 is about 273.8269148566.

The spelling of 20531865 in words is "twenty million, five hundred thirty-one thousand, eight hundred sixty-five".