1611860981 has 2 divisors, whose sum is σ = 1611860982. Its totient is φ = 1611860980.

The previous prime is 1611860969. The next prime is 1611861049. The reversal of 1611860981 is 1890681161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1526464900 + 85396081 = 39070^2 + 9241^2 .

It is an emirp because it is prime and its reverse (1890681161) is a distict prime. It is also a bemirp because it and its reverse can be mirrored producing other two distinct primes, 1860981191 and 1911890681.

It is a cyclic number.

It is not a de Polignac number, because 1611860981 - 2²² = 1607666677 is a prime.

It is a super-2 number, since 2×1611860981² = 5196191644140564722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1611860941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 805930490 + 805930491.

It is an arithmetic number, because the mean of its divisors is an integer number (805930491).

Almost surely, 2^1611860981 is an apocalyptic number.

It is an amenable number.

1611860981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1611860981 is an equidigital number, since it uses as much as digits as its factorization.

1611860981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20736, while the sum is 41.

The square root of 1611860981 is about 40147.9885050297. The cubic root of 1611860981 is about 1172.4901261362.

The spelling of 1611860981 in words is "one billion, six hundred eleven million, eight hundred sixty thousand, nine hundred eighty-one".