21420316720 has 80 divisors (see below), whose sum is σ = 54857417472. Its totient is φ = 7713550080.

The previous prime is 21420316699. The next prime is 21420316739. The reversal of 21420316720 is 2761302412.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×21420316720² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27522 + ... + 208801.

Almost surely, 2^21420316720 is an apocalyptic number.

21420316720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21420316720 is an abundant number, since it is smaller than the sum of its proper divisors (33437100752).

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

21420316720 is a wasteful number, since it uses less digits than its factorization.

21420316720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 236450 (or 236444 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 28.

The spelling of 21420316720 in words is "twenty-one billion, four hundred twenty million, three hundred sixteen thousand, seven hundred twenty".