21253118040 has 512 divisors, whose sum is σ = 92980224000. Its totient is φ = 4183488000.

The previous prime is 21253117969. The next prime is 21253118057. The reversal of 21253118040 is 4081135212.

21253118040 is a `hidden beast` number, since 2 + 12 + 531 + 1 + 80 + 40 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 21253117995 and 21253118013.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 1573315 + ... + 1586765.

It is an arithmetic number, because the mean of its divisors is an integer number (181602000).

Almost surely, 2^21253118040 is an apocalyptic number.

21253118040 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 21253118040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46490112000).

21253118040 is an abundant number, since it is smaller than the sum of its proper divisors (71727105960).

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

21253118040 is a wasteful number, since it uses less digits than its factorization.

21253118040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13508 (or 13498 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The spelling of 21253118040 in words is "twenty-one billion, two hundred fifty-three million, one hundred eighteen thousand, forty".