21491454 has 16 divisors (see below), whose sum is σ = 43170192. Its totient is φ = 7132608.

The previous prime is 21491441. The next prime is 21491461. The reversal of 21491454 is 45419412.

It is a super-3 number, since 3×21491454³ (a number of 23 digits) contains 333 as substring.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6289 + ... + 9084.

It is an arithmetic number, because the mean of its divisors is an integer number (2698137).

Almost surely, 2^21491454 is an apocalyptic number.

21491454 is an abundant number, since it is smaller than the sum of its proper divisors (21678738).

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

21491454 is a wasteful number, since it uses less digits than its factorization.

21491454 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15611.

The product of its digits is 5760, while the sum is 30.

The square root of 21491454 is about 4635.8876172746. The cubic root of 21491454 is about 278.0280409236.

It can be divided in two parts, 21491 and 454, that added together give a triangular number (21945 = T₂₀₉).

The spelling of 21491454 in words is "twenty-one million, four hundred ninety-one thousand, four hundred fifty-four".