661255617211 has 8 divisors (see below), whose sum is σ = 755761851104. Its totient is φ = 566759669760.

The previous prime is 661255617181. The next prime is 661255617229. The reversal of 661255617211 is 112716552166.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 661255617211 - 2²⁷ = 661121399483 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661255617311) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2433360 + ... + 2691421.

It is an arithmetic number, because the mean of its divisors is an integer number (94470231388).

Almost surely, 2^661255617211 is an apocalyptic number.

661255617211 is a deficient number, since it is larger than the sum of its proper divisors (94506233893).

661255617211 is a wasteful number, since it uses less digits than its factorization.

661255617211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5143221.

The product of its digits is 151200, while the sum is 43.

The spelling of 661255617211 in words is "six hundred sixty-one billion, two hundred fifty-five million, six hundred seventeen thousand, two hundred eleven".