21005514086400 has 432 divisors, whose sum is σ = 78014318873400. Its totient is φ = 5601467105280.

The previous prime is 21005514086387. The next prime is 21005514086477. The reversal of 21005514086400 is 468041550012.

It is a happy number.

21005514086400 is a `hidden beast` number, since 2 + 1 + 0 + 0 + 5 + 5 + 1 + 4 + 0 + 8 + 640 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (432).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

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 35 ways as a sum of consecutive naturals, for example, 11597436 + ... + 13285764.

Almost surely, 2^{21005514086400} is an apocalyptic number.

21005514086400 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 21005514086400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39007159436700).

21005514086400 is an abundant number, since it is smaller than the sum of its proper divisors (57008804787000).

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

21005514086400 is an equidigital number, since it uses as much as digits as its factorization.

21005514086400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1688376 (or 1688339 counting only the distinct ones).

The product of its (nonzero) digits is 38400, while the sum is 36.

The spelling of 21005514086400 in words is "twenty-one trillion, five billion, five hundred fourteen million, eighty-six thousand, four hundred".