21485100 has 144 divisors (see below), whose sum is σ = 76606208. Its totient is φ = 4527360.

The previous prime is 21485089. The next prime is 21485111. The reversal of 21485100 is 158412.

It is an interprime number because it is at equal distance from previous prime (21485089) and next prime (21485111).

It is a Harshad number since it is a multiple of its sum of digits (21).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 26907 + ... + 27693.

Almost surely, 2^21485100 is an apocalyptic number.

21485100 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 21485100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38303104).

21485100 is an abundant number, since it is smaller than the sum of its proper divisors (55121108).

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

21485100 is a wasteful number, since it uses less digits than its factorization.

21485100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 824 (or 817 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 21.

The square root of 21485100 is about 4635.2022609591. The cubic root of 21485100 is about 278.0006383368. Note that the first 3 decimals are identical.

The spelling of 21485100 in words is "twenty-one million, four hundred eighty-five thousand, one hundred".