7643981 has 16 divisors (see below), whose sum is σ = 8363520. Its totient is φ = 6966960.

The previous prime is 7643969. The next prime is 7644001. The reversal of 7643981 is 1893467.

It is a cyclic number.

It is not a de Polignac number, because 7643981 - 2¹⁴ = 7627597 is a prime.

It is a super-2 number, since 2×7643981² = 116860891056722, 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 (7643381) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 58286 + ... + 58416.

It is an arithmetic number, because the mean of its divisors is an integer number (522720).

Almost surely, 2^7643981 is an apocalyptic number.

It is an amenable number.

7643981 is a deficient number, since it is larger than the sum of its proper divisors (719539).

7643981 is a wasteful number, since it uses less digits than its factorization.

7643981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 256.

The product of its digits is 36288, while the sum is 38.

The square root of 7643981 is about 2764.7750360563. The cubic root of 7643981 is about 196.9880432847.

The spelling of 7643981 in words is "seven million, six hundred forty-three thousand, nine hundred eighty-one".