7138981 has 2 divisors, whose sum is σ = 7138982. Its totient is φ = 7138980.

The previous prime is 7138973. The next prime is 7138987. The reversal of 7138981 is 1898317.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5062500 + 2076481 = 2250^2 + 1441^2 .

It is an emirp because it is prime and its reverse (1898317) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 7138981 - 2³ = 7138973 is a prime.

It is a super-2 number, since 2×7138981² = 101930099436722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 7138981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7138987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3569490 + 3569491.

It is an arithmetic number, because the mean of its divisors is an integer number (3569491).

Almost surely, 2^7138981 is an apocalyptic number.

It is an amenable number.

7138981 is a deficient number, since it is larger than the sum of its proper divisors (1).

7138981 is an equidigital number, since it uses as much as digits as its factorization.

7138981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12096, while the sum is 37.

The square root of 7138981 is about 2671.8871607910. The cubic root of 7138981 is about 192.5508360707.

The spelling of 7138981 in words is "seven million, one hundred thirty-eight thousand, nine hundred eighty-one".