21491274 has 32 divisors (see below), whose sum is σ = 49821696. Its totient is φ = 6053040.

The previous prime is 21491263. The next prime is 21491287. The reversal of 21491274 is 47219412.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 622 + ... + 6585.

It is an arithmetic number, because the mean of its divisors is an integer number (1556928).

Almost surely, 2^21491274 is an apocalyptic number.

21491274 is an abundant number, since it is smaller than the sum of its proper divisors (28330422).

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

21491274 is a wasteful number, since it uses less digits than its factorization.

21491274 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7290.

The product of its digits is 4032, while the sum is 30.

The square root of 21491274 is about 4635.8682034760. The cubic root of 21491274 is about 278.0272647207.

The spelling of 21491274 in words is "twenty-one million, four hundred ninety-one thousand, two hundred seventy-four".