615978 has 64 divisors (see below), whose sum is σ = 1607040. Its totient is φ = 172800.

The previous prime is 615971. The next prime is 615997. The reversal of 615978 is 879516.

615978 is a `hidden beast` number, since 61 + 597 + 8 = 666.

It is not an unprimeable number, because it can be changed into a prime (615971) by changing a digit.

615978 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10068 + ... + 10128.

It is an arithmetic number, because the mean of its divisors is an integer number (25110).

2⁶¹⁵⁹⁷⁸ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 615978, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (803520).

615978 is an abundant number, since it is smaller than the sum of its proper divisors (991062).

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

615978 is a wasteful number, since it uses less digits than its factorization.

615978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100 (or 94 counting only the distinct ones).

The product of its digits is 15120, while the sum is 36.

The square root of 615978 is about 784.8426593910. The cubic root of 615978 is about 85.0854043567.

The spelling of 615978 in words is "six hundred fifteen thousand, nine hundred seventy-eight".