661535124 has 48 divisors (see below), whose sum is σ = 1599971520. Its totient is φ = 212486400.

The previous prime is 661535111. The next prime is 661535137. The reversal of 661535124 is 421535166.

It is an interprime number because it is at equal distance from previous prime (661535111) and next prime (661535137).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 207567 + ... + 210729.

It is an arithmetic number, because the mean of its divisors is an integer number (33332740).

Almost surely, 2^661535124 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 661535124, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (799985760).

661535124 is an abundant number, since it is smaller than the sum of its proper divisors (938436396).

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

661535124 is a wasteful number, since it uses less digits than its factorization.

661535124 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3800 (or 3798 counting only the distinct ones).

The product of its digits is 21600, while the sum is 33.

The square root of 661535124 is about 25720.3251145859. The cubic root of 661535124 is about 871.3332813633. Note that the first 3 decimals are identical.

The spelling of 661535124 in words is "six hundred sixty-one million, five hundred thirty-five thousand, one hundred twenty-four".