77913421 has 2 divisors, whose sum is σ = 77913422. Its totient is φ = 77913420.

The previous prime is 77913413. The next prime is 77913427. The reversal of 77913421 is 12431977.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 47817225 + 30096196 = 6915^2 + 5486^2 .

It is an emirp because it is prime and its reverse (12431977) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77913421 - 2³ = 77913413 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77913427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38956710 + 38956711.

It is an arithmetic number, because the mean of its divisors is an integer number (38956711).

Almost surely, 2^77913421 is an apocalyptic number.

It is an amenable number.

77913421 is a deficient number, since it is larger than the sum of its proper divisors (1).

77913421 is an equidigital number, since it uses as much as digits as its factorization.

77913421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10584, while the sum is 34.

The square root of 77913421 is about 8826.8579347353. The cubic root of 77913421 is about 427.1077230970.

The spelling of 77913421 in words is "seventy-seven million, nine hundred thirteen thousand, four hundred twenty-one".