721605516 has 24 divisors (see below), whose sum is σ = 1684947264. Its totient is φ = 240363600.

The previous prime is 721605481. The next prime is 721605517. The reversal of 721605516 is 615506127.

It is not an unprimeable number, because it can be changed into a prime (721605517) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3310 + ... + 38133.

It is an arithmetic number, because the mean of its divisors is an integer number (70206136).

Almost surely, 2^721605516 is an apocalyptic number.

It is an amenable number.

721605516 is an abundant number, since it is smaller than the sum of its proper divisors (963341748).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

721605516 is a wasteful number, since it uses less digits than its factorization.

721605516 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42901 (or 42899 counting only the distinct ones).

The product of its (nonzero) digits is 12600, while the sum is 33.

The square root of 721605516 is about 26862.7160949894. The cubic root of 721605516 is about 896.9466553910.

The spelling of 721605516 in words is "seven hundred twenty-one million, six hundred five thousand, five hundred sixteen".