615814981 has 2 divisors, whose sum is σ = 615814982. Its totient is φ = 615814980.

The previous prime is 615814963. The next prime is 615814993. The reversal of 615814981 is 189418516.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 443313025 + 172501956 = 21055^2 + 13134^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-615814981 is a prime.

It is a super-2 number, since 2×615814981² = 758456181648060722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (615814921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 307907490 + 307907491.

It is an arithmetic number, because the mean of its divisors is an integer number (307907491).

Almost surely, 2^615814981 is an apocalyptic number.

It is an amenable number.

615814981 is a deficient number, since it is larger than the sum of its proper divisors (1).

615814981 is an equidigital number, since it uses as much as digits as its factorization.

615814981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 69120, while the sum is 43.

The square root of 615814981 is about 24815.6196980853. The cubic root of 615814981 is about 850.7789772425.

The spelling of 615814981 in words is "six hundred fifteen million, eight hundred fourteen thousand, nine hundred eighty-one".