7581981 has 12 divisors (see below), whose sum is σ = 11112416. Its totient is φ = 4594920.

The previous prime is 7581953. The next prime is 7581989. The reversal of 7581981 is 1891857.

It is not a de Polignac number, because 7581981 - 2¹⁷ = 7450909 is a prime.

It is a super-2 number, since 2×7581981² = 114972871768722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7581989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10081 + ... + 10806.

Almost surely, 2^7581981 is an apocalyptic number.

It is an amenable number.

7581981 is a deficient number, since it is larger than the sum of its proper divisors (3530435).

7581981 is a wasteful number, since it uses less digits than its factorization.

7581981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20912 (or 20901 counting only the distinct ones).

The product of its digits is 20160, while the sum is 39.

The square root of 7581981 is about 2753.5397218853. The cubic root of 7581981 is about 196.4540096579.

The spelling of 7581981 in words is "seven million, five hundred eighty-one thousand, nine hundred eighty-one".