661158331 has 2 divisors, whose sum is σ = 661158332. Its totient is φ = 661158330.

The previous prime is 661158313. The next prime is 661158383. The reversal of 661158331 is 133851166.

Together with previous prime (661158313) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 661158331 - 2¹⁷ = 661027259 is a prime.

It is a super-2 number, since 2×661158331² = 874260677301411122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (661168331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330579165 + 330579166.

It is an arithmetic number, because the mean of its divisors is an integer number (330579166).

Almost surely, 2^661158331 is an apocalyptic number.

661158331 is a deficient number, since it is larger than the sum of its proper divisors (1).

661158331 is an equidigital number, since it uses as much as digits as its factorization.

661158331 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12960, while the sum is 34.

The square root of 661158331 is about 25712.9992610742. Note that the first 3 decimals coincide. The cubic root of 661158331 is about 871.1678204419.

The spelling of 661158331 in words is "six hundred sixty-one million, one hundred fifty-eight thousand, three hundred thirty-one".