661005007 has 4 divisors (see below), whose sum is σ = 711851560. Its totient is φ = 610158456.

The previous prime is 661004983. The next prime is 661005013. The reversal of 661005007 is 700500166.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 661005007 - 2⁷ = 661004879 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 (661005097) 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, 25423257 + ... + 25423282.

It is an arithmetic number, because the mean of its divisors is an integer number (177962890).

Almost surely, 2^661005007 is an apocalyptic number.

661005007 is a deficient number, since it is larger than the sum of its proper divisors (50846553).

661005007 is a wasteful number, since it uses less digits than its factorization.

661005007 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50846552.

The product of its (nonzero) digits is 1260, while the sum is 25.

The square root of 661005007 is about 25710.0176390449. The cubic root of 661005007 is about 871.1004733557.

The spelling of 661005007 in words is "six hundred sixty-one million, five thousand, seven".