21260413440 has 800 divisors, whose sum is σ = 88505835264. Its totient is φ = 4777574400.

The previous prime is 21260413411. The next prime is 21260413463. The reversal of 21260413440 is 4431406212.

It is a happy number.

21260413440 is a `hidden beast` number, since 2 + 1 + 2 + 604 + 13 + 4 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 140797365 + ... + 140797515.

Almost surely, 2^21260413440 is an apocalyptic number.

21260413440 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 21260413440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44252917632).

21260413440 is an abundant number, since it is smaller than the sum of its proper divisors (67245421824).

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

21260413440 is an equidigital number, since it uses as much as digits as its factorization.

21260413440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 290 (or 265 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 27.

Adding to 21260413440 its reverse (4431406212), we get a palindrome (25691819652).

The spelling of 21260413440 in words is "twenty-one billion, two hundred sixty million, four hundred thirteen thousand, four hundred forty".