611615981 has 2 divisors, whose sum is σ = 611615982. Its totient is φ = 611615980.

The previous prime is 611615969. The next prime is 611615993. The reversal of 611615981 is 189516116.

It is a balanced prime because it is at equal distance from previous prime (611615969) and next prime (611615993).

It can be written as a sum of positive squares in only one way, i.e., 314743081 + 296872900 = 17741^2 + 17230^2 .

It is a cyclic number.

It is not a de Polignac number, because 611615981 - 2²² = 607421677 is a prime.

It is a super-2 number, since 2×611615981² = 748148216429184722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (611615911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 305807990 + 305807991.

It is an arithmetic number, because the mean of its divisors is an integer number (305807991).

Almost surely, 2^611615981 is an apocalyptic number.

It is an amenable number.

611615981 is a deficient number, since it is larger than the sum of its proper divisors (1).

611615981 is an equidigital number, since it uses as much as digits as its factorization.

611615981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12960, while the sum is 38.

The square root of 611615981 is about 24730.8710117537. The cubic root of 611615981 is about 848.8408564440.

The spelling of 611615981 in words is "six hundred eleven million, six hundred fifteen thousand, nine hundred eighty-one".