27195637921 has 3 divisors (see below), whose sum is σ = 27195802833. Its totient is φ = 27195473010.

The previous prime is 27195637901. The next prime is 27195637957. The reversal of 27195637921 is 12973659172.

The square root of 27195637921 is 164911.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a de Polignac number, because none of the positive numbers 2^k-27195637921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (27195637901) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 82456 + ... + 247366.

It is an arithmetic number, because the mean of its divisors is an integer number (9065267611).

Almost surely, 2^27195637921 is an apocalyptic number.

27195637921 is the 164911-st square number.

27195637921 is the 82456-th centered octagonal number.

It is an amenable number.

27195637921 is a deficient number, since it is larger than the sum of its proper divisors (164912).

27195637921 is an frugal number, since it uses more digits than its factorization.

27195637921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 329822 (or 164911 counting only the distinct ones).

The product of its digits is 1428840, while the sum is 52.

The spelling of 27195637921 in words is "twenty-seven billion, one hundred ninety-five million, six hundred thirty-seven thousand, nine hundred twenty-one".