21523748 has 6 divisors (see below), whose sum is σ = 37666566. Its totient is φ = 10761872.

The previous prime is 21523741. The next prime is 21523753. The reversal of 21523748 is 84732512.

It can be written as a sum of positive squares in only one way, i.e., 19695844 + 1827904 = 4438^2 + 1352^2 .

It is not an unprimeable number, because it can be changed into a prime (21523741) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2690465 + ... + 2690472.

It is an arithmetic number, because the mean of its divisors is an integer number (6277761).

Almost surely, 2^21523748 is an apocalyptic number.

It is an amenable number.

21523748 is a deficient number, since it is larger than the sum of its proper divisors (16142818).

21523748 is a wasteful number, since it uses less digits than its factorization.

21523748 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5380941 (or 5380939 counting only the distinct ones).

The product of its digits is 13440, while the sum is 32.

The square root of 21523748 is about 4639.3693536945. The cubic root of 21523748 is about 278.1672302663.

The spelling of 21523748 in words is "twenty-one million, five hundred twenty-three thousand, seven hundred forty-eight".