21201927391 has 8 divisors (see below), whose sum is σ = 21233864960. Its totient is φ = 21170014848.

The previous prime is 21201927379. The next prime is 21201927401. The reversal of 21201927391 is 19372910212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21201927391 - 2³¹ = 19054443743 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21201927391.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21261927391) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2266075 + ... + 2275411.

It is an arithmetic number, because the mean of its divisors is an integer number (2654233120).

Almost surely, 2^21201927391 is an apocalyptic number.

21201927391 is a deficient number, since it is larger than the sum of its proper divisors (31937569).

21201927391 is a wasteful number, since it uses less digits than its factorization.

21201927391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12513.

The product of its (nonzero) digits is 13608, while the sum is 37.

The spelling of 21201927391 in words is "twenty-one billion, two hundred one million, nine hundred twenty-seven thousand, three hundred ninety-one".