78077749 has 2 divisors, whose sum is σ = 78077750. Its totient is φ = 78077748.

The previous prime is 78077731. The next prime is 78077759. The reversal of 78077749 is 94777087.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 58629649 + 19448100 = 7657^2 + 4410^2 .

It is a cyclic number.

It is not a de Polignac number, because 78077749 - 2¹⁹ = 77553461 is a prime.

It is a super-2 number, since 2×78077749² = 12192269777814002, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78077759) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39038874 + 39038875.

It is an arithmetic number, because the mean of its divisors is an integer number (39038875).

Almost surely, 2^78077749 is an apocalyptic number.

It is an amenable number.

78077749 is a deficient number, since it is larger than the sum of its proper divisors (1).

78077749 is an equidigital number, since it uses as much as digits as its factorization.

78077749 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 691488, while the sum is 49.

The square root of 78077749 is about 8836.1614403541. The cubic root of 78077749 is about 427.4077846765.

The spelling of 78077749 in words is "seventy-eight million, seventy-seven thousand, seven hundred forty-nine".