21454379091 has 16 divisors (see below), whose sum is σ = 31829634720. Its totient is φ = 14282503200.

The previous prime is 21454379087. The next prime is 21454379137. The reversal of 21454379091 is 19097345412.

21454379091 is a `hidden beast` number, since 2 + 1 + 45 + 437 + 90 + 91 = 666.

It is not a de Polignac number, because 21454379091 - 2² = 21454379087 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21454379081) 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, 547840 + ... + 585693.

It is an arithmetic number, because the mean of its divisors is an integer number (1989352170).

Almost surely, 2^21454379091 is an apocalyptic number.

21454379091 is a deficient number, since it is larger than the sum of its proper divisors (10375255629).

21454379091 is a wasteful number, since it uses less digits than its factorization.

21454379091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1134243 (or 1134237 counting only the distinct ones).

The product of its (nonzero) digits is 272160, while the sum is 45.

The spelling of 21454379091 in words is "twenty-one billion, four hundred fifty-four million, three hundred seventy-nine thousand, ninety-one".