21057662340 has 480 divisors, whose sum is σ = 82187892864. Its totient is φ = 4434186240.

The previous prime is 21057662293. The next prime is 21057662359. The reversal of 21057662340 is 4326675012.

21057662340 is a `hidden beast` number, since 21 + 0 + 5 + 7 + 6 + 623 + 4 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 21057662295 and 21057662304.

It is an unprimeable number.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 3935547 + ... + 3940893.

Almost surely, 2^21057662340 is an apocalyptic number.

21057662340 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 21057662340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41093946432).

21057662340 is an abundant number, since it is smaller than the sum of its proper divisors (61130230524).

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

21057662340 is a wasteful number, since it uses less digits than its factorization.

21057662340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5409 (or 5398 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 36.

The spelling of 21057662340 in words is "twenty-one billion, fifty-seven million, six hundred sixty-two thousand, three hundred forty".