21253748040 has 480 divisors, whose sum is σ = 82007902080. Its totient is φ = 4772452608.

The previous prime is 21253748029. The next prime is 21253748081. The reversal of 21253748040 is 4084735212.

It is a happy number.

21253748040 is a `hidden beast` number, since 2 + 1 + 2 + 537 + 4 + 80 + 40 = 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 = 21253747986 and 21253748004.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 57911937 + ... + 57912303.

It is an arithmetic number, because the mean of its divisors is an integer number (170849796).

Almost surely, 2^21253748040 is an apocalyptic number.

21253748040 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 21253748040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41003951040).

21253748040 is an abundant number, since it is smaller than the sum of its proper divisors (60754154040).

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

21253748040 is a wasteful number, since it uses less digits than its factorization.

21253748040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 479 (or 451 counting only the distinct ones).

The product of its (nonzero) digits is 53760, while the sum is 36.

The spelling of 21253748040 in words is "twenty-one billion, two hundred fifty-three million, seven hundred forty-eight thousand, forty".