720675421 has 2 divisors, whose sum is σ = 720675422. Its totient is φ = 720675420.

The previous prime is 720675419. The next prime is 720675427. The reversal of 720675421 is 124576027.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 564775225 + 155900196 = 23765^2 + 12486^2 .

It is a cyclic number.

It is not a de Polignac number, because 720675421 - 2¹ = 720675419 is a prime.

Together with 720675419, 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 (720675427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360337710 + 360337711.

It is an arithmetic number, because the mean of its divisors is an integer number (360337711).

Almost surely, 2^720675421 is an apocalyptic number.

It is an amenable number.

720675421 is a deficient number, since it is larger than the sum of its proper divisors (1).

720675421 is an equidigital number, since it uses as much as digits as its factorization.

720675421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23520, while the sum is 34.

The square root of 720675421 is about 26845.3985070067. The cubic root of 720675421 is about 896.5611242089.

The spelling of 720675421 in words is "seven hundred twenty million, six hundred seventy-five thousand, four hundred twenty-one".