661770013 has 4 divisors (see below), whose sum is σ = 661842720. Its totient is φ = 661697308.

The previous prime is 661769993. The next prime is 661770023. The reversal of 661770013 is 310077166.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-661770013 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 (661770023) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20353 + ... + 41686.

It is an arithmetic number, because the mean of its divisors is an integer number (165460680).

It is a 9102-hyperperfect number.

Almost surely, 2^661770013 is an apocalyptic number.

It is an amenable number.

661770013 is a deficient number, since it is larger than the sum of its proper divisors (72707).

661770013 is a wasteful number, since it uses less digits than its factorization.

661770013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72706.

The product of its (nonzero) digits is 5292, while the sum is 31.

The square root of 661770013 is about 25724.8909229952. The cubic root of 661770013 is about 871.4363962633.

The spelling of 661770013 in words is "six hundred sixty-one million, seven hundred seventy thousand, thirteen".