21097740867840 has 1944 divisors, whose sum is σ = 95365090050048. Its totient is φ = 4450848030720.

The previous prime is 21097740867821. The next prime is 21097740867883. The reversal of 21097740867840 is 4876804779012.

21097740867840 is a `hidden beast` number, since 2 + 1 + 0 + 97 + 7 + 408 + 67 + 84 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1944).

It is a super-2 number, since 2×21097740867840² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

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 215 ways as a sum of consecutive naturals, for example, 2575718145 + ... + 2575726335.

Almost surely, 2^{21097740867840} is an apocalyptic number.

21097740867840 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 21097740867840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47682545025024).

21097740867840 is an abundant number, since it is smaller than the sum of its proper divisors (74267349182208).

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

21097740867840 is an equidigital number, since it uses as much as digits as its factorization.

21097740867840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8267 (or 8221 counting only the distinct ones).

The product of its (nonzero) digits is 37933056, while the sum is 63.

The spelling of 21097740867840 in words is "twenty-one trillion, ninety-seven billion, seven hundred forty million, eight hundred sixty-seven thousand, eight hundred forty".