661493131 has 8 divisors (see below), whose sum is σ = 712701360. Its totient is φ = 610331232.

The previous prime is 661493111. The next prime is 661493213. The reversal of 661493131 is 131394166.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 661493131 - 2⁷ = 661493003 is a prime.

It is a super-2 number, since 2×661493131² = 875146324720366322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661493111) 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 7 ways as a sum of consecutive naturals, for example, 21621 + ... + 42313.

It is an arithmetic number, because the mean of its divisors is an integer number (89087670).

Almost surely, 2^661493131 is an apocalyptic number.

661493131 is a deficient number, since it is larger than the sum of its proper divisors (51208229).

661493131 is a wasteful number, since it uses less digits than its factorization.

661493131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23165.

The product of its digits is 11664, while the sum is 34.

The square root of 661493131 is about 25719.5087628049. The cubic root of 661493131 is about 871.3148441096.

The spelling of 661493131 in words is "six hundred sixty-one million, four hundred ninety-three thousand, one hundred thirty-one".