21451890991104 has 840 divisors, whose sum is σ = 76958551663488. Its totient is φ = 5931119738880.

The previous prime is 21451890991079. The next prime is 21451890991121. The reversal of 21451890991104 is 40119909815412.

21451890991104 is a `hidden beast` number, since 2 + 1 + 4 + 518 + 9 + 0 + 9 + 9 + 110 + 4 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 1007924847 + ... + 1007946129.

Almost surely, 2^{21451890991104} is an apocalyptic number.

21451890991104 is a gapful number since it is divisible by the number (24) 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 21451890991104, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38479275831744).

21451890991104 is an abundant number, since it is smaller than the sum of its proper divisors (55506660672384).

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

21451890991104 is an equidigital number, since it uses as much as digits as its factorization.

21451890991104 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21366 (or 21326 counting only the distinct ones).

The product of its (nonzero) digits is 933120, while the sum is 54.

The spelling of 21451890991104 in words is "twenty-one trillion, four hundred fifty-one billion, eight hundred ninety million, nine hundred ninety-one thousand, one hundred four".