21406774591 has 8 divisors (see below), whose sum is σ = 21760044768. Its totient is φ = 21053580000.

The previous prime is 21406774553. The next prime is 21406774639. The reversal of 21406774591 is 19547760412.

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 21406774591 - 2⁷ = 21406774463 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 (21406774511) 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, 1003941 + ... + 1025041.

It is an arithmetic number, because the mean of its divisors is an integer number (2720005596).

Almost surely, 2^21406774591 is an apocalyptic number.

21406774591 is a deficient number, since it is larger than the sum of its proper divisors (353270177).

21406774591 is a wasteful number, since it uses less digits than its factorization.

21406774591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37793.

The product of its (nonzero) digits is 423360, while the sum is 46.

The spelling of 21406774591 in words is "twenty-one billion, four hundred six million, seven hundred seventy-four thousand, five hundred ninety-one".