78573421 has 2 divisors, whose sum is σ = 78573422. Its totient is φ = 78573420.

The previous prime is 78573409. The next prime is 78573431. The reversal of 78573421 is 12437587.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 73102500 + 5470921 = 8550^2 + 2339^2 .

It is a cyclic number.

It is not a de Polignac number, because 78573421 - 2⁹ = 78572909 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78573431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39286710 + 39286711.

It is an arithmetic number, because the mean of its divisors is an integer number (39286711).

Almost surely, 2^78573421 is an apocalyptic number.

It is an amenable number.

78573421 is a deficient number, since it is larger than the sum of its proper divisors (1).

78573421 is an equidigital number, since it uses as much as digits as its factorization.

78573421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 47040, while the sum is 37.

The square root of 78573421 is about 8864.1649916955. The cubic root of 78573421 is about 428.3103351653.

The spelling of 78573421 in words is "seventy-eight million, five hundred seventy-three thousand, four hundred twenty-one".