21403546640 has 160 divisors (see below), whose sum is σ = 58326100224. Its totient is φ = 7153090560.

The previous prime is 21403546589. The next prime is 21403546649. The reversal of 21403546640 is 4664530412.

It is a super-2 number, since 2×21403546640² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a self number, because there is not a number n which added to its sum of digits gives 21403546640.

It is not an unprimeable number, because it can be changed into a prime (21403546649) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3636500 + ... + 3642380.

Almost surely, 2^21403546640 is an apocalyptic number.

21403546640 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 21403546640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29163050112).

21403546640 is an abundant number, since it is smaller than the sum of its proper divisors (36922553584).

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

21403546640 is a wasteful number, since it uses less digits than its factorization.

21403546640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6065 (or 6059 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 35.

The spelling of 21403546640 in words is "twenty-one billion, four hundred three million, five hundred forty-six thousand, six hundred forty".