21006834380 has 48 divisors (see below), whose sum is σ = 53382079296. Its totient is φ = 6778675200.

The previous prime is 21006834367. The next prime is 21006834403. The reversal of 21006834380 is 8343860012.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a self number, because there is not a number n which added to its sum of digits gives 21006834380.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4410821 + ... + 4415580.

It is an arithmetic number, because the mean of its divisors is an integer number (1112126652).

Almost surely, 2^21006834380 is an apocalyptic number.

21006834380 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21006834380 is an abundant number, since it is smaller than the sum of its proper divisors (32375244916).

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

21006834380 is a wasteful number, since it uses less digits than its factorization.

21006834380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8826434 (or 8826432 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 35.

The spelling of 21006834380 in words is "twenty-one billion, six million, eight hundred thirty-four thousand, three hundred eighty".