661929072 has 80 divisors (see below), whose sum is σ = 1957350912. Its totient is φ = 188824320.

The previous prime is 661929061. The next prime is 661929091. The reversal of 661929072 is 270929166.

661929072 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (42).

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, 296922 + ... + 299142.

Almost surely, 2^661929072 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 661929072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (978675456).

661929072 is an abundant number, since it is smaller than the sum of its proper divisors (1295421840).

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

661929072 is a wasteful number, since it uses less digits than its factorization.

661929072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3126 (or 3120 counting only the distinct ones).

The product of its (nonzero) digits is 81648, while the sum is 42.

The square root of 661929072 is about 25727.9822761133. The cubic root of 661929072 is about 871.5062083810.

The spelling of 661929072 in words is "six hundred sixty-one million, nine hundred twenty-nine thousand, seventy-two".