51091000 has 64 divisors (see below), whose sum is σ = 125892000. Its totient is φ = 19353600.

The previous prime is 51090997. The next prime is 51091031. The reversal of 51091000 is 19015.

It is a super-2 number, since 2×51091000² = 5220580562000000, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17656 + ... + 20344.

Almost surely, 2^51091000 is an apocalyptic number.

51091000 is a gapful number since it is divisible by the number (50) 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 51091000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (62946000).

51091000 is an abundant number, since it is smaller than the sum of its proper divisors (74801000).

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

51091000 is a wasteful number, since it uses less digits than its factorization.

51091000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2729 (or 2715 counting only the distinct ones).

The product of its (nonzero) digits is 45, while the sum is 16.

The square root of 51091000 is about 7147.7968633699. The cubic root of 51091000 is about 371.0634126077.

The spelling of 51091000 in words is "fifty-one million, ninety-one thousand".