7321981 has 4 divisors (see below), whose sum is σ = 7640352. Its totient is φ = 7003612.

The previous prime is 7321969. The next prime is 7321987. The reversal of 7321981 is 1891237.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1891237 = 1277 ⋅1481.

It is a cyclic number.

It is not a de Polignac number, because 7321981 - 2⁹ = 7321469 is a prime.

It is a super-2 number, since 2×7321981² = 107222811528722, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a nialpdrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7321987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 159151 + ... + 159196.

It is an arithmetic number, because the mean of its divisors is an integer number (1910088).

Almost surely, 2^7321981 is an apocalyptic number.

It is an amenable number.

7321981 is a deficient number, since it is larger than the sum of its proper divisors (318371).

7321981 is a wasteful number, since it uses less digits than its factorization.

7321981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 318370.

The product of its digits is 3024, while the sum is 31.

The square root of 7321981 is about 2705.9159262623. The cubic root of 7321981 is about 194.1822515893.

The spelling of 7321981 in words is "seven million, three hundred twenty-one thousand, nine hundred eighty-one".