661951007 has 4 divisors (see below), whose sum is σ = 662040120. Its totient is φ = 661861896.

The previous prime is 661951001. The next prime is 661951009. The reversal of 661951007 is 700159166.

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 661951007 - 2¹² = 661946911 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 (661951001) 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, 32288 + ... + 48645.

It is an arithmetic number, because the mean of its divisors is an integer number (165510030).

Almost surely, 2^661951007 is an apocalyptic number.

661951007 is a deficient number, since it is larger than the sum of its proper divisors (89113).

661951007 is an equidigital number, since it uses as much as digits as its factorization.

661951007 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89112.

The product of its (nonzero) digits is 11340, while the sum is 35.

The square root of 661951007 is about 25728.4085594115. The cubic root of 661951007 is about 871.5158349298.

The spelling of 661951007 in words is "six hundred sixty-one million, nine hundred fifty-one thousand, seven".