661142831 has 2 divisors, whose sum is σ = 661142832. Its totient is φ = 661142830.

The previous prime is 661142803. The next prime is 661142837. The reversal of 661142831 is 138241166.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 661142831 - 2²⁶ = 594033967 is a prime.

It is a super-2 number, since 2×661142831² = 874219685965389122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661142837) 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 as a sum of consecutive naturals, namely, 330571415 + 330571416.

It is an arithmetic number, because the mean of its divisors is an integer number (330571416).

Almost surely, 2^661142831 is an apocalyptic number.

661142831 is a deficient number, since it is larger than the sum of its proper divisors (1).

661142831 is an equidigital number, since it uses as much as digits as its factorization.

661142831 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6912, while the sum is 32.

The square root of 661142831 is about 25712.6978553399. The cubic root of 661142831 is about 871.1610125886.

Adding to 661142831 its reverse (138241166), we get a palindrome (799383997).

The spelling of 661142831 in words is "six hundred sixty-one million, one hundred forty-two thousand, eight hundred thirty-one".