21053100 has 36 divisors (see below), whose sum is σ = 60914504. Its totient is φ = 5614080.

The previous prime is 21053099. The next prime is 21053107. The reversal of 21053100 is 135012.

It is a super-2 number, since 2×21053100² = 886466039220000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is not an unprimeable number, because it can be changed into a prime (21053107) 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, 34789 + ... + 35388.

Almost surely, 2^21053100 is an apocalyptic number.

21053100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21053100 is an abundant number, since it is smaller than the sum of its proper divisors (39861404).

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

21053100 is a wasteful number, since it uses less digits than its factorization.

21053100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70194 (or 70187 counting only the distinct ones).

The product of its (nonzero) digits is 30, while the sum is 12.

The square root of 21053100 is about 4588.3657221281. The cubic root of 21053100 is about 276.1247598116.

Adding to 21053100 its reverse (135012), we get a palindrome (21188112).

The spelling of 21053100 in words is "twenty-one million, fifty-three thousand, one hundred".