21747344 has 10 divisors (see below), whose sum is σ = 42135510. Its totient is φ = 10873664.

The previous prime is 21747289. The next prime is 21747347. The reversal of 21747344 is 44374712.

It can be written as a sum of positive squares in only one way, i.e., 14348944 + 7398400 = 3788^2 + 2720^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21747344.

It is not an unprimeable number, because it can be changed into a prime (21747347) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 679589 + ... + 679620.

It is an arithmetic number, because the mean of its divisors is an integer number (4213551).

Almost surely, 2^21747344 is an apocalyptic number.

It is an amenable number.

21747344 is a deficient number, since it is larger than the sum of its proper divisors (20388166).

21747344 is a wasteful number, since it uses less digits than its factorization.

21747344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1359217 (or 1359211 counting only the distinct ones).

The product of its digits is 18816, while the sum is 32.

The square root of 21747344 is about 4663.4047647615. The cubic root of 21747344 is about 279.1271457927.

The spelling of 21747344 in words is "twenty-one million, seven hundred forty-seven thousand, three hundred forty-four".