21019257000 has 512 divisors, whose sum is σ = 84365798400. Its totient is φ = 4800902400.

The previous prime is 21019256989. The next prime is 21019257013. The reversal of 21019257000 is 75291012.

21019257000 is a `hidden beast` number, since 2 + 1 + 0 + 1 + 92 + 570 + 0 + 0 = 666.

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

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, 15308314 + ... + 15309686.

It is an arithmetic number, because the mean of its divisors is an integer number (164776950).

Almost surely, 2^21019257000 is an apocalyptic number.

21019257000 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 21019257000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42182899200).

21019257000 is an abundant number, since it is smaller than the sum of its proper divisors (63346541400).

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

21019257000 is an equidigital number, since it uses as much as digits as its factorization.

21019257000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1422 (or 1390 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 27.

The spelling of 21019257000 in words is "twenty-one billion, nineteen million, two hundred fifty-seven thousand".