851021920 has 192 divisors, whose sum is σ = 2402942976. Its totient is φ = 278691840.

The previous prime is 851021911. The next prime is 851021923. The reversal of 851021920 is 29120158.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (851021923) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4409344 + ... + 4409536.

It is an arithmetic number, because the mean of its divisors is an integer number (12515328).

Almost surely, 2^851021920 is an apocalyptic number.

851021920 is a gapful number since it is divisible by the number (80) 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 851021920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1201471488).

851021920 is an abundant number, since it is smaller than the sum of its proper divisors (1551921056).

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

851021920 is a wasteful number, since it uses less digits than its factorization.

851021920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 373 (or 365 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 28.

The square root of 851021920 is about 29172.2799931716. The cubic root of 851021920 is about 947.6477056855.

The spelling of 851021920 in words is "eight hundred fifty-one million, twenty-one thousand, nine hundred twenty".