20861375 has 16 divisors (see below), whose sum is σ = 26225472. Its totient is φ = 16567200.

The previous prime is 20861371. The next prime is 20861389. The reversal of 20861375 is 57316802.

It is a happy number.

It is not a de Polignac number, because 20861375 - 2² = 20861371 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20861371) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19094 + ... + 20156.

It is an arithmetic number, because the mean of its divisors is an integer number (1639092).

Almost surely, 2^20861375 is an apocalyptic number.

20861375 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

20861375 is a deficient number, since it is larger than the sum of its proper divisors (5364097).

20861375 is a wasteful number, since it uses less digits than its factorization.

20861375 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1235 (or 1225 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 32.

The square root of 20861375 is about 4567.4254235838. The cubic root of 20861375 is about 275.2840041166.

The spelling of 20861375 in words is "twenty million, eight hundred sixty-one thousand, three hundred seventy-five".