721522755 has 128 divisors (see below), whose sum is σ = 1447891200. Its totient is φ = 339075072.

The previous prime is 721522723. The next prime is 721522771. The reversal of 721522755 is 557225127.

It is not a de Polignac number, because 721522755 - 2⁵ = 721522723 is a prime.

Together with 726368445 it forms an amicable pair .

721522755 is a modest number, since divided by 22755 gives 7215 as remainder.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 2462389 + ... + 2462681.

It is an arithmetic number, because the mean of its divisors is an integer number (11311650).

Almost surely, 2^721522755 is an apocalyptic number.

721522755 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

721522755 is a wasteful number, since it uses less digits than its factorization.

721522755 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 390 (or 384 counting only the distinct ones).

The product of its digits is 49000, while the sum is 36.

The square root of 721522755 is about 26861.1756071844. The cubic root of 721522755 is about 896.9123637831.

The spelling of 721522755 in words is "seven hundred twenty-one million, five hundred twenty-two thousand, seven hundred fifty-five".