21249140 has 24 divisors (see below), whose sum is σ = 48680352. Its totient is φ = 7726880.

The previous prime is 21249127. The next prime is 21249143. The reversal of 21249140 is 4194212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21249143) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48074 + ... + 48513.

It is an arithmetic number, because the mean of its divisors is an integer number (2028348).

Almost surely, 2^21249140 is an apocalyptic number.

21249140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21249140 is an abundant number, since it is smaller than the sum of its proper divisors (27431212).

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

21249140 is a wasteful number, since it uses less digits than its factorization.

21249140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96607 (or 96605 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 21249140 is about 4609.6789476058. The cubic root of 21249140 is about 276.9791762335.

The spelling of 21249140 in words is "twenty-one million, two hundred forty-nine thousand, one hundred forty".