661056390 has 160 divisors (see below), whose sum is σ = 1915350624. Its totient is φ = 162984960.

The previous prime is 661056367. The next prime is 661056397. The reversal of 661056390 is 93650166.

661056390 is a `hidden beast` number, since 6 + 6 + 1 + 0 + 563 + 90 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661056397) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 839577 + ... + 840363.

Almost surely, 2^661056390 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661056390, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (957675312).

661056390 is an abundant number, since it is smaller than the sum of its proper divisors (1254294234).

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

661056390 is a wasteful number, since it uses less digits than its factorization.

661056390 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 884 (or 875 counting only the distinct ones).

The product of its (nonzero) digits is 29160, while the sum is 36.

The square root of 661056390 is about 25711.0168993760. The cubic root of 661056390 is about 871.1230443374.

The spelling of 661056390 in words is "six hundred sixty-one million, fifty-six thousand, three hundred ninety".