21051981397227 has 16 divisors (see below), whose sum is σ = 30621265355520. Its totient is φ = 12758692644000.

The previous prime is 21051981397201. The next prime is 21051981397229. The reversal of 21051981397227 is 72279318915012.

It is not a de Polignac number, because 21051981397227 - 2⁶ = 21051981397163 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21051981397229) 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, 3190674 + ... + 7230792.

It is an arithmetic number, because the mean of its divisors is an integer number (1913829084720).

Almost surely, 2^{21051981397227} is an apocalyptic number.

21051981397227 is a deficient number, since it is larger than the sum of its proper divisors (9569283958293).

21051981397227 is a wasteful number, since it uses less digits than its factorization.

21051981397227 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4198034.

The product of its (nonzero) digits is 3810240, while the sum is 57.

The spelling of 21051981397227 in words is "twenty-one trillion, fifty-one billion, nine hundred eighty-one million, three hundred ninety-seven thousand, two hundred twenty-seven".