21379494340 has 12 divisors (see below), whose sum is σ = 44896938156. Its totient is φ = 8551797728.

The previous prime is 21379494319. The next prime is 21379494341. The reversal of 21379494340 is 4349497312.

It can be written as a sum of positive squares in 2 ways, for example, as 16358921604 + 5020572736 = 127902^2 + 70856^2 .

It is not an unprimeable number, because it can be changed into a prime (21379494341) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 534487339 + ... + 534487378.

It is an arithmetic number, because the mean of its divisors is an integer number (3741411513).

Almost surely, 2^21379494340 is an apocalyptic number.

21379494340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21379494340 is an abundant number, since it is smaller than the sum of its proper divisors (23517443816).

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

21379494340 is a wasteful number, since it uses less digits than its factorization.

21379494340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1068974726 (or 1068974724 counting only the distinct ones).

The product of its (nonzero) digits is 653184, while the sum is 46.

The spelling of 21379494340 in words is "twenty-one billion, three hundred seventy-nine million, four hundred ninety-four thousand, three hundred forty".