1891061256 has 128 divisors (see below), whose sum is σ = 5599272960. Its totient is φ = 520819200.

The previous prime is 1891061239. The next prime is 1891061273. The reversal of 1891061256 is 6521601981.

It is an interprime number because it is at equal distance from previous prime (1891061239) and next prime (1891061273).

It is a super-2 number, since 2×1891061256² = 7152225347888595072, which contains 22 as substring.

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, 1723300 + ... + 1724396.

It is an arithmetic number, because the mean of its divisors is an integer number (43744320).

Almost surely, 2^1891061256 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1891061256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2799636480).

1891061256 is an abundant number, since it is smaller than the sum of its proper divisors (3708211704).

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

1891061256 is a wasteful number, since it uses less digits than its factorization.

1891061256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1475 (or 1471 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 39.

The square root of 1891061256 is about 43486.3341292411. The cubic root of 1891061256 is about 1236.6169613909.

The spelling of 1891061256 in words is "one billion, eight hundred ninety-one million, sixty-one thousand, two hundred fifty-six".