21307073440 has 24 divisors (see below), whose sum is σ = 50337961380. Its totient is φ = 8522829312.

The previous prime is 21307073399. The next prime is 21307073441. The reversal of 21307073440 is 4437070312.

It can be written as a sum of positive squares in 2 ways, for example, as 20019986064 + 1287087376 = 141492^2 + 35876^2 .

It is not an unprimeable number, because it can be changed into a prime (21307073441) 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, 66584445 + ... + 66584764.

Almost surely, 2^21307073440 is an apocalyptic number.

21307073440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21307073440 is an abundant number, since it is smaller than the sum of its proper divisors (29030887940).

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

21307073440 is a wasteful number, since it uses less digits than its factorization.

21307073440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133169224 (or 133169216 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 31.

The spelling of 21307073440 in words is "twenty-one billion, three hundred seven million, seventy-three thousand, four hundred forty".