21275400 has 96 divisors (see below), whose sum is σ = 67183200. Its totient is φ = 5568000.

The previous prime is 21275399. The next prime is 21275461. The reversal of 21275400 is 457212.

21275400 = T₄₇₀ + T₄₇₁ + ... + T₆₁₃.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 35100 + ... + 35700.

It is an arithmetic number, because the mean of its divisors is an integer number (699825).

Almost surely, 2^21275400 is an apocalyptic number.

21275400 is a gapful number since it is divisible by the number (20) 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 21275400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33591600).

21275400 is an abundant number, since it is smaller than the sum of its proper divisors (45907800).

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

21275400 is a wasteful number, since it uses less digits than its factorization.

21275400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 679 (or 670 counting only the distinct ones).

The product of its (nonzero) digits is 560, while the sum is 21.

The square root of 21275400 is about 4612.5264226885. The cubic root of 21275400 is about 277.0932275787.

The spelling of 21275400 in words is "twenty-one million, two hundred seventy-five thousand, four hundred".