661142958 has 64 divisors (see below), whose sum is σ = 1615444992. Its totient is φ = 176267520.

The previous prime is 661142953. The next prime is 661142959. The reversal of 661142958 is 859241166.

It is a super-2 number, since 2×661142958² = 874220021825979528, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661142953) 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 31 ways as a sum of consecutive naturals, for example, 31260 + ... + 47952.

It is an arithmetic number, because the mean of its divisors is an integer number (25241328).

Almost surely, 2^661142958 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661142958, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (807722496).

661142958 is an abundant number, since it is smaller than the sum of its proper divisors (954302034).

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

661142958 is a wasteful number, since it uses less digits than its factorization.

661142958 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16769.

The product of its digits is 103680, while the sum is 42.

The square root of 661142958 is about 25712.7003249367. The cubic root of 661142958 is about 871.1610683695.

The spelling of 661142958 in words is "six hundred sixty-one million, one hundred forty-two thousand, nine hundred fifty-eight".