21591354 has 16 divisors (see below), whose sum is σ = 43242048. Its totient is φ = 7187232.

The previous prime is 21591347. The next prime is 21591373. The reversal of 21591354 is 45319512.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3294 + ... + 7350.

It is an arithmetic number, because the mean of its divisors is an integer number (2702628).

Almost surely, 2^21591354 is an apocalyptic number.

21591354 is an abundant number, since it is smaller than the sum of its proper divisors (21650694).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21591354 is a wasteful number, since it uses less digits than its factorization.

21591354 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4949.

The product of its digits is 5400, while the sum is 30.

The square root of 21591354 is about 4646.6497608492. The cubic root of 21591354 is about 278.4581665605.

It can be divided in two parts, 21591 and 354, that added together give a triangular number (21945 = T₂₀₉).

The spelling of 21591354 in words is "twenty-one million, five hundred ninety-one thousand, three hundred fifty-four".