721854402123 has 4 divisors (see below), whose sum is σ = 962472536168. Its totient is φ = 481236268080.

The previous prime is 721854402121. The next prime is 721854402131. The reversal of 721854402123 is 321204458127.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 721854402123 - 2¹ = 721854402121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (721854402121) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 120309067018 + ... + 120309067023.

It is an arithmetic number, because the mean of its divisors is an integer number (240618134042).

Almost surely, 2^721854402123 is an apocalyptic number.

721854402123 is a deficient number, since it is larger than the sum of its proper divisors (240618134045).

721854402123 is a wasteful number, since it uses less digits than its factorization.

721854402123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 240618134044.

The product of its (nonzero) digits is 107520, while the sum is 39.

The spelling of 721854402123 in words is "seven hundred twenty-one billion, eight hundred fifty-four million, four hundred two thousand, one hundred twenty-three".