661022207 has 4 divisors (see below), whose sum is σ = 682345536. Its totient is φ = 639698880.

The previous prime is 661022191. The next prime is 661022221. The reversal of 661022207 is 702220166.

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 661022207 - 2⁴ = 661022191 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 (661025207) 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, 10661618 + ... + 10661679.

It is an arithmetic number, because the mean of its divisors is an integer number (170586384).

Almost surely, 2^661022207 is an apocalyptic number.

661022207 is a deficient number, since it is larger than the sum of its proper divisors (21323329).

661022207 is a wasteful number, since it uses less digits than its factorization.

661022207 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21323328.

The product of its (nonzero) digits is 2016, while the sum is 26.

The square root of 661022207 is about 25710.3521368339. The cubic root of 661022207 is about 871.1080289203.

The spelling of 661022207 in words is "six hundred sixty-one million, twenty-two thousand, two hundred seven".