21254004 has 18 divisors (see below), whose sum is σ = 53725490. Its totient is φ = 7084656.

The previous prime is 21253993. The next prime is 21254017. The reversal of 21254004 is 40045212.

It can be written as a sum of positive squares in only one way, i.e., 20250000 + 1004004 = 4500^2 + 1002^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 295159 + ... + 295230.

Almost surely, 2^21254004 is an apocalyptic number.

It is an amenable number.

21254004 is an abundant number, since it is smaller than the sum of its proper divisors (32471486).

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

21254004 is a wasteful number, since it uses less digits than its factorization.

21254004 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 590399 (or 590394 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 18.

The square root of 21254004 is about 4610.2065029671. The cubic root of 21254004 is about 277.0003084445. Note that the first 3 decimals are identical.

Adding to 21254004 its reverse (40045212), we get a palindrome (61299216).

The spelling of 21254004 in words is "twenty-one million, two hundred fifty-four thousand, four".