661313061 has 6 divisors (see below), whose sum is σ = 955229990. Its totient is φ = 440875368.

The previous prime is 661313033. The next prime is 661313083. The reversal of 661313061 is 160313166.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 639128961 + 22184100 = 25281^2 + 4710^2 .

It is not a de Polignac number, because 661313061 - 2¹⁴ = 661296677 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661313011) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 36739606 + ... + 36739623.

Almost surely, 2^661313061 is an apocalyptic number.

It is an amenable number.

661313061 is a deficient number, since it is larger than the sum of its proper divisors (293916929).

661313061 is a wasteful number, since it uses less digits than its factorization.

661313061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73479235 (or 73479232 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 27.

The square root of 661313061 is about 25716.0078744738. The cubic root of 661313061 is about 871.2357745544.

The spelling of 661313061 in words is "six hundred sixty-one million, three hundred thirteen thousand, sixty-one".