661372992 has 336 divisors, whose sum is σ = 2314163520. Its totient is φ = 184633344.

The previous prime is 661372969. The next prime is 661372993. The reversal of 661372992 is 299273166.

It is a happy number.

661372992 is a `hidden beast` number, since 6 + 613 + 7 + 29 + 9 + 2 = 666.

It is a tau number, because it is divible by the number of its divisors (336).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (661372993) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 6181003 + ... + 6181109.

Almost surely, 2^661372992 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 661372992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1157081760).

661372992 is an abundant number, since it is smaller than the sum of its proper divisors (1652790528).

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

661372992 is a wasteful number, since it uses less digits than its factorization.

661372992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215 (or 192 counting only the distinct ones).

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

The square root of 661372992 is about 25717.1730950352. The cubic root of 661372992 is about 871.2620921222.

The spelling of 661372992 in words is "six hundred sixty-one million, three hundred seventy-two thousand, nine hundred ninety-two".