21691332732427 has 16 divisors (see below), whose sum is σ = 22766038567488. Its totient is φ = 20627602047360.

The previous prime is 21691332732347. The next prime is 21691332732449. The reversal of 21691332732427 is 72423723319612.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21691332732427 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21691332732467) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 147232933 + ... + 147380185.

It is an arithmetic number, because the mean of its divisors is an integer number (1422877410468).

Almost surely, 2^{21691332732427} is an apocalyptic number.

21691332732427 is a deficient number, since it is larger than the sum of its proper divisors (1074705835061).

21691332732427 is a wasteful number, since it uses less digits than its factorization.

21691332732427 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 184470.

The product of its digits is 4572288, while the sum is 52.

The spelling of 21691332732427 in words is "twenty-one trillion, six hundred ninety-one billion, three hundred thirty-two million, seven hundred thirty-two thousand, four hundred twenty-seven".