21161607776 has 12 divisors (see below), whose sum is σ = 41661915372. Its totient is φ = 10580803872.

The previous prime is 21161607773. The next prime is 21161607799. The reversal of 21161607776 is 67770616112.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21161607773) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330650090 + ... + 330650153.

It is an arithmetic number, because the mean of its divisors is an integer number (3471826281).

Almost surely, 2^21161607776 is an apocalyptic number.

It is an amenable number.

21161607776 is a deficient number, since it is larger than the sum of its proper divisors (20500307596).

21161607776 is an equidigital number, since it uses as much as digits as its factorization.

21161607776 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 661300253 (or 661300245 counting only the distinct ones).

The product of its (nonzero) digits is 148176, while the sum is 44.

The spelling of 21161607776 in words is "twenty-one billion, one hundred sixty-one million, six hundred seven thousand, seven hundred seventy-six".