21085625418 has 64 divisors (see below), whose sum is σ = 49574149632. Its totient is φ = 5894470080.

The previous prime is 21085625401. The next prime is 21085625437. The reversal of 21085625418 is 81452658012.

It is a self number, because there is not a number n which added to its sum of digits gives 21085625418.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1595305 + ... + 1608467.

It is an arithmetic number, because the mean of its divisors is an integer number (774596088).

Almost surely, 2^21085625418 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21085625418, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24787074816).

21085625418 is an abundant number, since it is smaller than the sum of its proper divisors (28488524214).

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

21085625418 is a wasteful number, since it uses less digits than its factorization.

21085625418 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15059.

The product of its (nonzero) digits is 153600, while the sum is 42.

The spelling of 21085625418 in words is "twenty-one billion, eighty-five million, six hundred twenty-five thousand, four hundred eighteen".