21383740 has 48 divisors (see below), whose sum is σ = 54028800. Its totient is φ = 6944832.

The previous prime is 21383723. The next prime is 21383749. The reversal of 21383740 is 4738312.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a junction number, because it is equal to n+sod(n) for n = 21383699 and 21383708.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21383749) 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 15 ways as a sum of consecutive naturals, for example, 1360 + ... + 6679.

It is an arithmetic number, because the mean of its divisors is an integer number (1125600).

Almost surely, 2^21383740 is an apocalyptic number.

21383740 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21383740 is an abundant number, since it is smaller than the sum of its proper divisors (32645060).

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

21383740 is a wasteful number, since it uses less digits than its factorization.

21383740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8074 (or 8072 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 28.

The square root of 21383740 is about 4624.2556157721. The cubic root of 21383740 is about 277.5627756148.

The spelling of 21383740 in words is "twenty-one million, three hundred eighty-three thousand, seven hundred forty".