1581988 has 12 divisors (see below), whose sum is σ = 2777292. Its totient is φ = 788480.

The previous prime is 1581949. The next prime is 1582001. The reversal of 1581988 is 8891851.

It can be written as a sum of positive squares in 2 ways, for example, as 675684 + 906304 = 822^2 + 952^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 1581988.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2148 + ... + 2788.

It is an arithmetic number, because the mean of its divisors is an integer number (231441).

2^1581988 is an apocalyptic number.

It is an amenable number.

1581988 is a deficient number, since it is larger than the sum of its proper divisors (1195304).

1581988 is a wasteful number, since it uses less digits than its factorization.

1581988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1262 (or 1260 counting only the distinct ones).

The product of its digits is 23040, while the sum is 40.

The square root of 1581988 is about 1257.7710443479. The cubic root of 1581988 is about 116.5201571340.

It can be divided in two parts, 1581 and 988, that multiplied together give a triangular number (1562028 = T₁₇₆₇).

The spelling of 1581988 in words is "one million, five hundred eighty-one thousand, nine hundred eighty-eight".