20195977667661 has 24 divisors (see below), whose sum is σ = 30889585714104. Its totient is φ = 12671321425920.

The previous prime is 20195977667617. The next prime is 20195977667711. The reversal of 20195977667661 is 16676677959102.

20195977667661 is a `hidden beast` number, since 20 + 1 + 9 + 597 + 7 + 6 + 6 + 7 + 6 + 6 + 1 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 7101212336100 + 13094765331561 = 2664810^2 + 3618669^2 .

It is not a de Polignac number, because 20195977667661 - 2⁶ = 20195977667597 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20195977667661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20195977668661) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 526186 + ... + 6377211.

It is an arithmetic number, because the mean of its divisors is an integer number (1287066071421).

Almost surely, 2^{20195977667661} is an apocalyptic number.

It is an amenable number.

20195977667661 is a deficient number, since it is larger than the sum of its proper divisors (10693608046443).

20195977667661 is a wasteful number, since it uses less digits than its factorization.

20195977667661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6922541 (or 6922538 counting only the distinct ones).

The product of its (nonzero) digits is 360067680, while the sum is 72.

The spelling of 20195977667661 in words is "twenty trillion, one hundred ninety-five billion, nine hundred seventy-seven million, six hundred sixty-seven thousand, six hundred sixty-one".