661862831 has 4 divisors (see below), whose sum is σ = 756414672. Its totient is φ = 567310992.

The previous prime is 661862801. The next prime is 661862849. The reversal of 661862831 is 138268166.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 661862831 - 2¹⁰ = 661861807 is a prime.

It is a super-2 number, since 2×661862831² = 876124814118669122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661862801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 47275910 + ... + 47275923.

It is an arithmetic number, because the mean of its divisors is an integer number (189103668).

Almost surely, 2^661862831 is an apocalyptic number.

661862831 is a deficient number, since it is larger than the sum of its proper divisors (94551841).

661862831 is an equidigital number, since it uses as much as digits as its factorization.

661862831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94551840.

The product of its digits is 82944, while the sum is 41.

The square root of 661862831 is about 25726.6949101512. The cubic root of 661862831 is about 871.4771360977.

The spelling of 661862831 in words is "six hundred sixty-one million, eight hundred sixty-two thousand, eight hundred thirty-one".