21375504 has 60 divisors (see below), whose sum is σ = 60611200. Its totient is φ = 7031232.

The previous prime is 21375503. The next prime is 21375517. The reversal of 21375504 is 40557312.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21375503) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10437 + ... + 12315.

Almost surely, 2^21375504 is an apocalyptic number.

21375504 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21375504, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30305600).

21375504 is an abundant number, since it is smaller than the sum of its proper divisors (39235696).

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

21375504 is a wasteful number, since it uses less digits than its factorization.

21375504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1972 (or 1963 counting only the distinct ones).

The product of its (nonzero) digits is 4200, while the sum is 27.

The square root of 21375504 is about 4623.3650083029. The cubic root of 21375504 is about 277.5271363772.

The spelling of 21375504 in words is "twenty-one million, three hundred seventy-five thousand, five hundred four".