21356147240 has 32 divisors (see below), whose sum is σ = 49223318760. Its totient is φ = 8334105600.

The previous prime is 21356147221. The next prime is 21356147249. The reversal of 21356147240 is 4274165312.

It can be written as a sum of positive squares in 4 ways, for example, as 9910998916 + 11445148324 = 99554^2 + 106982^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21356147240.

It is not an unprimeable number, because it can be changed into a prime (21356147249) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6509381 + ... + 6512660.

Almost surely, 2^21356147240 is an apocalyptic number.

21356147240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21356147240 is an abundant number, since it is smaller than the sum of its proper divisors (27867171520).

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

21356147240 is a wasteful number, since it uses less digits than its factorization.

21356147240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13022093 (or 13022089 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 35.

The spelling of 21356147240 in words is "twenty-one billion, three hundred fifty-six million, one hundred forty-seven thousand, two hundred forty".