721253999 has 4 divisors (see below), whose sum is σ = 721514664. Its totient is φ = 720993336.

The previous prime is 721253969. The next prime is 721254013. The reversal of 721253999 is 999352127.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 999352127 = 379 ⋅2636813.

It is a cyclic number.

It is not a de Polignac number, because 721253999 - 2¹⁶ = 721188463 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721253909) 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, 126137 + ... + 131730.

It is an arithmetic number, because the mean of its divisors is an integer number (180378666).

Almost surely, 2^721253999 is an apocalyptic number.

721253999 is a deficient number, since it is larger than the sum of its proper divisors (260665).

721253999 is a wasteful number, since it uses less digits than its factorization.

721253999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 260664.

The product of its digits is 306180, while the sum is 47.

The square root of 721253999 is about 26856.1724562530. The cubic root of 721253999 is about 896.8009879866.

The spelling of 721253999 in words is "seven hundred twenty-one million, two hundred fifty-three thousand, nine hundred ninety-nine".