721428730 has 32 divisors (see below), whose sum is σ = 1423785600. Its totient is φ = 261011520.

The previous prime is 721428703. The next prime is 721428791. The reversal of 721428730 is 37824127.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5412 + ... + 38368.

It is an arithmetic number, because the mean of its divisors is an integer number (44493300).

Almost surely, 2^721428730 is an apocalyptic number.

721428730 is a deficient number, since it is larger than the sum of its proper divisors (702356870).

721428730 is a wasteful number, since it uses less digits than its factorization.

721428730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33174.

The product of its (nonzero) digits is 18816, while the sum is 34.

The square root of 721428730 is about 26859.4253475386. The cubic root of 721428730 is about 896.8734018109.

The spelling of 721428730 in words is "seven hundred twenty-one million, four hundred twenty-eight thousand, seven hundred thirty".