21253004 has 6 divisors (see below), whose sum is σ = 37192764. Its totient is φ = 10626500.

The previous prime is 21252997. The next prime is 21253007. The reversal of 21253004 is 40035212.

It is not an unprimeable number, because it can be changed into a prime (21253007) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2656622 + ... + 2656629.

It is an arithmetic number, because the mean of its divisors is an integer number (6198794).

Almost surely, 2^21253004 is an apocalyptic number.

It is an amenable number.

21253004 is a deficient number, since it is larger than the sum of its proper divisors (15939760).

21253004 is a wasteful number, since it uses less digits than its factorization.

21253004 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5313255 (or 5313253 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 17.

The square root of 21253004 is about 4610.0980466797. The cubic root of 21253004 is about 276.9959640921.

Adding to 21253004 its reverse (40035212), we get a palindrome (61288216).

The spelling of 21253004 in words is "twenty-one million, two hundred fifty-three thousand, four".