21047248780 has 24 divisors (see below), whose sum is σ = 44310572208. Its totient is φ = 8397690048.

The previous prime is 21047248777. The next prime is 21047248801. The reversal of 21047248780 is 8784274012.

It is a super-2 number, since 2×21047248780² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1317454 + ... + 1333333.

It is an arithmetic number, because the mean of its divisors is an integer number (1846273842).

Almost surely, 2^21047248780 is an apocalyptic number.

21047248780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21047248780 is an abundant number, since it is smaller than the sum of its proper divisors (23263323428).

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

21047248780 is a wasteful number, since it uses less digits than its factorization.

21047248780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2651193 (or 2651191 counting only the distinct ones).

The product of its (nonzero) digits is 200704, while the sum is 43.

The spelling of 21047248780 in words is "twenty-one billion, forty-seven million, two hundred forty-eight thousand, seven hundred eighty".