21493254666240 has 1344 divisors, whose sum is σ = 88667938457280. Its totient is φ = 4896058245120.

The previous prime is 21493254666151. The next prime is 21493254666269. The reversal of 21493254666240 is 4266645239412.

It is a tau number, because it is divible by the number of its divisors (1344).

It is a super-2 number, since 2×21493254666240² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 111 ways as a sum of consecutive naturals, for example, 21999236632 + ... + 21999237608.

It is an arithmetic number, because the mean of its divisors is an integer number (65973168495).

Almost surely, 2^{21493254666240} is an apocalyptic number.

21493254666240 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 21493254666240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44333969228640).

21493254666240 is an abundant number, since it is smaller than the sum of its proper divisors (67174683791040).

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

21493254666240 is an frugal number, since it uses more digits than its factorization.

21493254666240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1450 (or 1415 counting only the distinct ones).

The product of its (nonzero) digits is 14929920, while the sum is 54.

The spelling of 21493254666240 in words is "twenty-one trillion, four hundred ninety-three billion, two hundred fifty-four million, six hundred sixty-six thousand, two hundred forty".