21317775480 has 128 divisors (see below), whose sum is σ = 71114760000. Its totient is φ = 5680300032.

The previous prime is 21317775473. The next prime is 21317775497. The reversal of 21317775480 is 8457771312.

21317775480 is a `hidden beast` number, since 2 + 1 + 31 + 7 + 77 + 548 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1514716 + ... + 1528724.

Almost surely, 2^21317775480 is an apocalyptic number.

21317775480 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21317775480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35557380000).

21317775480 is an abundant number, since it is smaller than the sum of its proper divisors (49796984520).

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

21317775480 is a wasteful number, since it uses less digits than its factorization.

21317775480 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15438 (or 15428 counting only the distinct ones).

The product of its (nonzero) digits is 329280, while the sum is 45.

The spelling of 21317775480 in words is "twenty-one billion, three hundred seventeen million, seven hundred seventy-five thousand, four hundred eighty".