216861625 has 16 divisors (see below), whose sum is σ = 277963920. Its totient is φ = 168796800.

The previous prime is 216861607. The next prime is 216861629. The reversal of 216861625 is 526168612.

It can be written as a sum of positive squares in 8 ways, for example, as 29637136 + 187224489 = 5444^2 + 13683^2 .

It is not a de Polignac number, because 216861625 - 2²³ = 208473017 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is not an unprimeable number, because it can be changed into a prime (216861629) 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, 18820 + ... + 28069.

It is an arithmetic number, because the mean of its divisors is an integer number (17372745).

Almost surely, 2^216861625 is an apocalyptic number.

216861625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

216861625 is a deficient number, since it is larger than the sum of its proper divisors (61102295).

216861625 is an equidigital number, since it uses as much as digits as its factorization.

216861625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46941 (or 46931 counting only the distinct ones).

The product of its digits is 34560, while the sum is 37.

The square root of 216861625 is about 14726.2223601302. Note that the first 3 decimals coincide. The cubic root of 216861625 is about 600.7967424600.

The spelling of 216861625 in words is "two hundred sixteen million, eight hundred sixty-one thousand, six hundred twenty-five".