21261772127 has 8 divisors (see below), whose sum is σ = 21970696320. Its totient is φ = 20554289280.

The previous prime is 21261772117. The next prime is 21261772139. The reversal of 21261772127 is 72127716212.

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 21261772127 - 2¹⁴ = 21261755743 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21261772117) 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, 330302 + ... + 389387.

It is an arithmetic number, because the mean of its divisors is an integer number (2746337040).

Almost surely, 2^21261772127 is an apocalyptic number.

21261772127 is a deficient number, since it is larger than the sum of its proper divisors (708924193).

21261772127 is an equidigital number, since it uses as much as digits as its factorization.

21261772127 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 720673.

The product of its digits is 32928, while the sum is 38.

The spelling of 21261772127 in words is "twenty-one billion, two hundred sixty-one million, seven hundred seventy-two thousand, one hundred twenty-seven".