615990 has 16 divisors (see below), whose sum is σ = 1478448. Its totient is φ = 164256.

The previous prime is 615971. The next prime is 615997. The reversal of 615990 is 99516.

615990 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (30), and also a Moran number because the ratio is a prime number: 20533 = 615990 / (6 + 1 + 5 + 9 + 9 + 0).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (615997) by changing a digit.

615990 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 7 ways as a sum of consecutive naturals, for example, 10237 + ... + 10296.

It is an arithmetic number, because the mean of its divisors is an integer number (92403).

2⁶¹⁵⁹⁹⁰ is an apocalyptic number.

615990 is an abundant number, since it is smaller than the sum of its proper divisors (862458).

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

615990 is a wasteful number, since it uses less digits than its factorization.

615990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20543.

The product of its (nonzero) digits is 2430, while the sum is 30.

The square root of 615990 is about 784.8503041982. The cubic root of 615990 is about 85.0859568755.

The spelling of 615990 in words is "six hundred fifteen thousand, nine hundred ninety".