1581361026 has 80 divisors (see below), whose sum is σ = 3809718528. Its totient is φ = 437119200.

The previous prime is 1581361009. The next prime is 1581361043. The reversal of 1581361026 is 6201631851.

It is an interprime number because it is at equal distance from previous prime (1581361009) and next prime (1581361043).

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 444816 + ... + 448356.

Almost surely, 2^1581361026 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1581361026, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1904859264).

1581361026 is an abundant number, since it is smaller than the sum of its proper divisors (2228357502).

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

1581361026 is an equidigital number, since it uses as much as digits as its factorization.

1581361026 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3605 (or 3584 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 33.

The square root of 1581361026 is about 39766.3303059259. The cubic root of 1581361026 is about 1165.0476199781.

Adding to 1581361026 its reverse (6201631851), we get a palindrome (7782992877).

The spelling of 1581361026 in words is "one billion, five hundred eighty-one million, three hundred sixty-one thousand, twenty-six".