21007100 has 18 divisors (see below), whose sum is σ = 45585624. Its totient is φ = 8402800.

The previous prime is 21007099. The next prime is 21007111. The reversal of 21007100 is 170012.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 104936 + ... + 105135.

Almost surely, 2^21007100 is an apocalyptic number.

21007100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21007100 is an abundant number, since it is smaller than the sum of its proper divisors (24578524).

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

21007100 is a wasteful number, since it uses less digits than its factorization.

21007100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 210085 (or 210078 counting only the distinct ones).

The product of its (nonzero) digits is 14, while the sum is 11.

The square root of 21007100 is about 4583.3503029989. The cubic root of 21007100 is about 275.9235067722.

Adding to 21007100 its reverse (170012), we get a palindrome (21177112).

The spelling of 21007100 in words is "twenty-one million, seven thousand, one hundred".