661899985269 has 4 divisors (see below), whose sum is σ = 882533313696. Its totient is φ = 441266656844.

The previous prime is 661899985231. The next prime is 661899985319. The reversal of 661899985269 is 962589998166.

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 661899985269 - 2⁷ = 661899985141 is a prime.

It is a super-2 number, since 2×661899985269² (a number of 24 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 661899985194 and 661899985203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661899986269) 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, 110316664209 + ... + 110316664214.

It is an arithmetic number, because the mean of its divisors is an integer number (220633328424).

Almost surely, 2^661899985269 is an apocalyptic number.

It is an amenable number.

661899985269 is a deficient number, since it is larger than the sum of its proper divisors (220633328427).

661899985269 is a wasteful number, since it uses less digits than its factorization.

661899985269 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220633328426.

The product of its digits is 906992640, while the sum is 78.

The spelling of 661899985269 in words is "six hundred sixty-one billion, eight hundred ninety-nine million, nine hundred eighty-five thousand, two hundred sixty-nine".