7810981 has 4 divisors (see below), whose sum is σ = 7958412. Its totient is φ = 7663552.

The previous prime is 7810931. The next prime is 7810987. The reversal of 7810981 is 1890187.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1890187 = 13 ⋅145399.

It can be written as a sum of positive squares in 2 ways, for example, as 5022081 + 2788900 = 2241^2 + 1670^2 .

It is a cyclic number.

It is not a de Polignac number, because 7810981 - 2¹⁵ = 7778213 is a prime.

It is a super-2 number, since 2×7810981² = 122022848364722, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

7810981 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7810987) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 73636 + ... + 73741.

It is an arithmetic number, because the mean of its divisors is an integer number (1989603).

Almost surely, 2^7810981 is an apocalyptic number.

It is an amenable number.

7810981 is a deficient number, since it is larger than the sum of its proper divisors (147431).

7810981 is a wasteful number, since it uses less digits than its factorization.

7810981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 147430.

The product of its (nonzero) digits is 4032, while the sum is 34.

The square root of 7810981 is about 2794.8132316847. The cubic root of 7810981 is about 198.4122705974.

The spelling of 7810981 in words is "seven million, eight hundred ten thousand, nine hundred eighty-one".