21271665742 has 4 divisors (see below), whose sum is σ = 31907498616. Its totient is φ = 10635832870.

The previous prime is 21271665719. The next prime is 21271665761. The reversal of 21271665742 is 24756617212.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5317916434 + ... + 5317916437.

It is an arithmetic number, because the mean of its divisors is an integer number (7976874654).

Almost surely, 2^21271665742 is an apocalyptic number.

21271665742 is a deficient number, since it is larger than the sum of its proper divisors (10635832874).

21271665742 is a wasteful number, since it uses less digits than its factorization.

21271665742 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10635832873.

The product of its digits is 282240, while the sum is 43.

The spelling of 21271665742 in words is "twenty-one billion, two hundred seventy-one million, six hundred sixty-five thousand, seven hundred forty-two".