77663381 has 2 divisors, whose sum is σ = 77663382. Its totient is φ = 77663380.

The previous prime is 77663359. The next prime is 77663413. The reversal of 77663381 is 18336677.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 76282756 + 1380625 = 8734^2 + 1175^2 .

It is an emirp because it is prime and its reverse (18336677) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77663381 - 2¹⁰ = 77662357 is a prime.

It is a super-2 number, since 2×77663381² = 12063201496702322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77663281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38831690 + 38831691.

It is an arithmetic number, because the mean of its divisors is an integer number (38831691).

Almost surely, 2^77663381 is an apocalyptic number.

It is an amenable number.

77663381 is a deficient number, since it is larger than the sum of its proper divisors (1).

77663381 is an equidigital number, since it uses as much as digits as its factorization.

77663381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 127008, while the sum is 41.

The square root of 77663381 is about 8812.6829626397. The cubic root of 77663381 is about 426.6503416470.

The spelling of 77663381 in words is "seventy-seven million, six hundred sixty-three thousand, three hundred eighty-one".