21035654640 has 1920 divisors, whose sum is σ = 104825290752. Its totient is φ = 3777269760.

The previous prime is 21035654587. The next prime is 21035654657. The reversal of 21035654640 is 4645653012.

21035654640 is a `hidden beast` number, since 2 + 1 + 0 + 3 + 5 + 6 + 5 + 4 + 640 = 666.

It is a super-2 number, since 2×21035654640² (a number of 21 digits) contains 22 as substring.

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 = 21035654595 and 21035654604.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 383 ways as a sum of consecutive naturals, for example, 447567097 + ... + 447567143.

Almost surely, 2^21035654640 is an apocalyptic number.

21035654640 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 21035654640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (52412645376).

21035654640 is an abundant number, since it is smaller than the sum of its proper divisors (83789636112).

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

21035654640 is a wasteful number, since it uses less digits than its factorization.

21035654640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129 (or 111 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 36.

The spelling of 21035654640 in words is "twenty-one billion, thirty-five million, six hundred fifty-four thousand, six hundred forty".