3639978 has 20 divisors (see below), whose sum is σ = 8156610. Its totient is φ = 1213272.

The previous prime is 3639973. The next prime is 3639983. The reversal of 3639978 is 8799363.

It is a happy number.

3639978 is a `hidden beast` number, since 3 + 639 + 9 + 7 + 8 = 666.

It is an interprime number because it is at equal distance from previous prime (3639973) and next prime (3639983).

It can be written as a sum of positive squares in only one way, i.e., 2712609 + 927369 = 1647^2 + 963^2 .

It is a plaindrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (3639971) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 11073 + ... + 11396.

Almost surely, 2^3639978 is an apocalyptic number.

3639978 is an abundant number, since it is smaller than the sum of its proper divisors (4516632).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

3639978 is a wasteful number, since it uses less digits than its factorization.

3639978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22483 (or 22474 counting only the distinct ones).

The product of its digits is 244944, while the sum is 45.

The square root of 3639978 is about 1907.8726372586. The cubic root of 3639978 is about 153.8271237103.

The spelling of 3639978 in words is "three million, six hundred thirty-nine thousand, nine hundred seventy-eight".