77421397 has 2 divisors, whose sum is σ = 77421398. Its totient is φ = 77421396.

The previous prime is 77421389. The next prime is 77421403. The reversal of 77421397 is 79312477.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 66438801 + 10982596 = 8151^2 + 3314^2 .

It is a cyclic number.

It is not a de Polignac number, because 77421397 - 2³ = 77421389 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77421307) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38710698 + 38710699.

It is an arithmetic number, because the mean of its divisors is an integer number (38710699).

Almost surely, 2^77421397 is an apocalyptic number.

It is an amenable number.

77421397 is a deficient number, since it is larger than the sum of its proper divisors (1).

77421397 is an equidigital number, since it uses as much as digits as its factorization.

77421397 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 74088, while the sum is 40.

The square root of 77421397 is about 8798.9429478773. The cubic root of 77421397 is about 426.2067607776.

The spelling of 77421397 in words is "seventy-seven million, four hundred twenty-one thousand, three hundred ninety-seven".