21251025054 has 112 divisors (see below), whose sum is σ = 54824984928. Its totient is φ = 6048997056.

The previous prime is 21251025041. The next prime is 21251025067. The reversal of 21251025054 is 45052015212.

It is an interprime number because it is at equal distance from previous prime (21251025041) and next prime (21251025067).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 2823304 + ... + 2830820.

It is an arithmetic number, because the mean of its divisors is an integer number (489508794).

Almost surely, 2^21251025054 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21251025054, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27412492464).

21251025054 is an abundant number, since it is smaller than the sum of its proper divisors (33573959874).

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

21251025054 is an equidigital number, since it uses as much as digits as its factorization.

21251025054 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7821 (or 7806 counting only the distinct ones).

The product of its (nonzero) digits is 4000, while the sum is 27.

The spelling of 21251025054 in words is "twenty-one billion, two hundred fifty-one million, twenty-five thousand, fifty-four".