21015007100 has 72 divisors (see below), whose sum is σ = 46010388480. Its totient is φ = 8331180480.

The previous prime is 21015007087. The next prime is 21015007121. The reversal of 21015007100 is 170051012.

It is a congruent number.

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, 5327729 + ... + 5331671.

Almost surely, 2^21015007100 is an apocalyptic number.

21015007100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21015007100 is an abundant number, since it is smaller than the sum of its proper divisors (24995381380).

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

21015007100 is a wasteful number, since it uses less digits than its factorization.

21015007100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4419 (or 4412 counting only the distinct ones).

The product of its (nonzero) digits is 70, while the sum is 17.

Adding to 21015007100 its reverse (170051012), we get a palindrome (21185058112).

The spelling of 21015007100 in words is "twenty-one billion, fifteen million, seven thousand, one hundred".