615648640 has 128 divisors (see below), whose sum is σ = 1563170400. Its totient is φ = 231211008.

The previous prime is 615648637. The next prime is 615648643. The reversal of 615648640 is 46846516.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (615648637) and next prime (615648643).

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 615648593 and 615648602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (615648643) 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, 2395392 + ... + 2395648.

Almost surely, 2^615648640 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 615648640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (781585200).

615648640 is an abundant number, since it is smaller than the sum of its proper divisors (947521760).

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

615648640 is a wasteful number, since it uses less digits than its factorization.

615648640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 492 (or 480 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 40.

The square root of 615648640 is about 24812.2679334236. The cubic root of 615648640 is about 850.7023675603.

The spelling of 615648640 in words is "six hundred fifteen million, six hundred forty-eight thousand, six hundred forty".