77217947 has 2 divisors, whose sum is σ = 77217948. Its totient is φ = 77217946.

The previous prime is 77217937. The next prime is 77217953. The reversal of 77217947 is 74971277.

It is a strong prime.

It is an emirp because it is prime and its reverse (74971277) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77217947 - 2¹⁸ = 76955803 is a prime.

It is a super-2 number, since 2×77217947² = 11925222677789618, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 77217898 and 77217907.

It is not a weakly prime, because it can be changed into another prime (77217937) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38608973 + 38608974.

It is an arithmetic number, because the mean of its divisors is an integer number (38608974).

Almost surely, 2^77217947 is an apocalyptic number.

77217947 is a deficient number, since it is larger than the sum of its proper divisors (1).

77217947 is an equidigital number, since it uses as much as digits as its factorization.

77217947 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 172872, while the sum is 44.

The square root of 77217947 is about 8787.3742949757. The cubic root of 77217947 is about 425.8331008058.

The spelling of 77217947 in words is "seventy-seven million, two hundred seventeen thousand, nine hundred forty-seven".