21402512040 has 192 divisors, whose sum is σ = 80436101760. Its totient is φ = 4515678720.

The previous prime is 21402512009. The next prime is 21402512051. The reversal of 21402512040 is 4021520412.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a junction number, because it is equal to n+sod(n) for n = 21402511998 and 21402512016.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 63556 + ... + 216435.

It is an arithmetic number, because the mean of its divisors is an integer number (418938030).

Almost surely, 2^21402512040 is an apocalyptic number.

21402512040 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 21402512040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40218050880).

21402512040 is an abundant number, since it is smaller than the sum of its proper divisors (59033589720).

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

21402512040 is a wasteful number, since it uses less digits than its factorization.

21402512040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 280032 (or 280021 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 21.

The spelling of 21402512040 in words is "twenty-one billion, four hundred two million, five hundred twelve thousand, forty".