21481640730 has 144 divisors (see below), whose sum is σ = 64306423584. Its totient is φ = 4933500480.

The previous prime is 21481640647. The next prime is 21481640779. The reversal of 21481640730 is 3704618412.

21481640730 is a `hidden beast` number, since 2 + 1 + 4 + 8 + 1 + 640 + 7 + 3 + 0 = 666.

It is a super-2 number, since 2×21481640730² (a number of 21 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 327337 + ... + 387443.

It is an arithmetic number, because the mean of its divisors is an integer number (446572386).

Almost surely, 2^21481640730 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21481640730, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32153211792).

21481640730 is an abundant number, since it is smaller than the sum of its proper divisors (42824782854).

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

21481640730 is a wasteful number, since it uses less digits than its factorization.

21481640730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60169 (or 60147 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 36.

The spelling of 21481640730 in words is "twenty-one billion, four hundred eighty-one million, six hundred forty thousand, seven hundred thirty".