77940013 has 2 divisors, whose sum is σ = 77940014. Its totient is φ = 77940012.

The previous prime is 77940011. The next prime is 77940029. The reversal of 77940013 is 31004977.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 45198729 + 32741284 = 6723^2 + 5722^2 .

It is an emirp because it is prime and its reverse (31004977) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77940013 - 2¹ = 77940011 is a prime.

Together with 77940011, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77940011) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38970006 + 38970007.

It is an arithmetic number, because the mean of its divisors is an integer number (38970007).

Almost surely, 2^77940013 is an apocalyptic number.

It is an amenable number.

77940013 is a deficient number, since it is larger than the sum of its proper divisors (1).

77940013 is an equidigital number, since it uses as much as digits as its factorization.

77940013 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5292, while the sum is 31.

The square root of 77940013 is about 8828.3641180006. The cubic root of 77940013 is about 427.1563084650.

The spelling of 77940013 in words is "seventy-seven million, nine hundred forty thousand, thirteen".