661275213 has 4 divisors (see below), whose sum is σ = 881700288. Its totient is φ = 440850140.

The previous prime is 661275187. The next prime is 661275227. The reversal of 661275213 is 312572166.

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.

It is a cyclic number.

It is not a de Polignac number, because 661275213 - 2⁹ = 661274701 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661275233) 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, 110212533 + ... + 110212538.

It is an arithmetic number, because the mean of its divisors is an integer number (220425072).

Almost surely, 2^661275213 is an apocalyptic number.

It is an amenable number.

661275213 is a deficient number, since it is larger than the sum of its proper divisors (220425075).

661275213 is a wasteful number, since it uses less digits than its factorization.

661275213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220425074.

The product of its digits is 15120, while the sum is 33.

The square root of 661275213 is about 25715.2719798955. The cubic root of 661275213 is about 871.2191535002.

The spelling of 661275213 in words is "six hundred sixty-one million, two hundred seventy-five thousand, two hundred thirteen".