721749428 has 48 divisors (see below), whose sum is σ = 1354254720. Its totient is φ = 335591424.

The previous prime is 721749403. The next prime is 721749449. The reversal of 721749428 is 824947127.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1072100 + ... + 1072772.

It is an arithmetic number, because the mean of its divisors is an integer number (28213640).

Almost surely, 2^721749428 is an apocalyptic number.

It is an amenable number.

721749428 is a deficient number, since it is larger than the sum of its proper divisors (632505292).

721749428 is a wasteful number, since it uses less digits than its factorization.

721749428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 936 (or 934 counting only the distinct ones).

The product of its digits is 225792, while the sum is 44.

The square root of 721749428 is about 26865.3946183562. The cubic root of 721749428 is about 897.0062783679.

The spelling of 721749428 in words is "seven hundred twenty-one million, seven hundred forty-nine thousand, four hundred twenty-eight".