21402744 has 32 divisors (see below), whose sum is σ = 58371840. Its totient is φ = 6485600.

The previous prime is 21402739. The next prime is 21402763. The reversal of 21402744 is 44720412.

It is a hoax number, since the sum of its digits (24) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

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, 40272 + ... + 40799.

It is an arithmetic number, because the mean of its divisors is an integer number (1824120).

Almost surely, 2^21402744 is an apocalyptic number.

21402744 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21402744 is an abundant number, since it is smaller than the sum of its proper divisors (36969096).

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

21402744 is a wasteful number, since it uses less digits than its factorization.

21402744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81091 (or 81087 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 24.

The square root of 21402744 is about 4626.3099766445. The cubic root of 21402744 is about 277.6449757844.

It can be divided in two parts, 2140 and 2744, that added together give a palindrome (4884).

The spelling of 21402744 in words is "twenty-one million, four hundred two thousand, seven hundred forty-four".