661992611069 has 4 divisors (see below), whose sum is σ = 662000170620. Its totient is φ = 661985051520.

The previous prime is 661992611057. The next prime is 661992611099. The reversal of 661992611069 is 960116299166.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 440139364900 + 221853246169 = 663430^2 + 471013^2 .

It is a cyclic number.

It is not a de Polignac number, because 661992611069 - 2¹² = 661992606973 is a prime.

It is a super-2 number, since 2×661992611069² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661992611009) 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, 3646862 + ... + 3824079.

It is an arithmetic number, because the mean of its divisors is an integer number (165500042655).

Almost surely, 2^661992611069 is an apocalyptic number.

It is an amenable number.

661992611069 is a deficient number, since it is larger than the sum of its proper divisors (7559551).

661992611069 is an equidigital number, since it uses as much as digits as its factorization.

661992611069 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7559550.

The product of its (nonzero) digits is 1889568, while the sum is 56.

The spelling of 661992611069 in words is "six hundred sixty-one billion, nine hundred ninety-two million, six hundred eleven thousand, sixty-nine".