21491480 has 16 divisors (see below), whose sum is σ = 48355920. Its totient is φ = 8596576.

The previous prime is 21491473. The next prime is 21491513. The reversal of 21491480 is 8419412.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 268604 + ... + 268683.

It is an arithmetic number, because the mean of its divisors is an integer number (3022245).

Almost surely, 2^21491480 is an apocalyptic number.

21491480 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21491480 is an abundant number, since it is smaller than the sum of its proper divisors (26864440).

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

21491480 is a wasteful number, since it uses less digits than its factorization.

21491480 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 537298 (or 537294 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 21491480 is about 4635.8904214832. The cubic root of 21491480 is about 278.0281530414.

The spelling of 21491480 in words is "twenty-one million, four hundred ninety-one thousand, four hundred eighty".