21254100 has 144 divisors (see below), whose sum is σ = 72912000. Its totient is φ = 4677120.

The previous prime is 21254099. The next prime is 21254117. The reversal of 21254100 is 145212.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21254100.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 60726 + ... + 61074.

Almost surely, 2^21254100 is an apocalyptic number.

21254100 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 21254100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36456000).

21254100 is an abundant number, since it is smaller than the sum of its proper divisors (51657900).

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

21254100 is a wasteful number, since it uses less digits than its factorization.

21254100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 402 (or 395 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 15.

The square root of 21254100 is about 4610.2169146364. The cubic root of 21254100 is about 277.0007254952. Note that the first 3 decimals are identical.

Adding to 21254100 its reverse (145212), we get a palindrome (21399312).

It can be divided in two parts, 21 and 254100, that multiplied together give a square (5336100 = 2310²).

The spelling of 21254100 in words is "twenty-one million, two hundred fifty-four thousand, one hundred".