21247877700 has 216 divisors, whose sum is σ = 76280742720. Its totient is φ = 4846060800.

The previous prime is 21247877681. The next prime is 21247877747. The reversal of 21247877700 is 777874212.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 3089866 + ... + 3096734.

Almost surely, 2^21247877700 is an apocalyptic number.

21247877700 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 21247877700, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38140371360).

21247877700 is an abundant number, since it is smaller than the sum of its proper divisors (55032865020).

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

21247877700 is a wasteful number, since it uses less digits than its factorization.

21247877700 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7387 (or 7377 counting only the distinct ones).

The product of its (nonzero) digits is 307328, while the sum is 45.

The spelling of 21247877700 in words is "twenty-one billion, two hundred forty-seven million, eight hundred seventy-seven thousand, seven hundred".