720521901 has 24 divisors (see below), whose sum is σ = 1139726016. Its totient is φ = 435003840.

The previous prime is 720521881. The next prime is 720521903. The reversal of 720521901 is 109125027.

It is not a de Polignac number, because 720521901 - 2⁷ = 720521773 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (720521903) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12201 + ... + 39873.

It is an arithmetic number, because the mean of its divisors is an integer number (47488584).

Almost surely, 2^720521901 is an apocalyptic number.

It is an amenable number.

720521901 is a deficient number, since it is larger than the sum of its proper divisors (419204115).

720521901 is a wasteful number, since it uses less digits than its factorization.

720521901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27953 (or 27950 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 27.

The square root of 720521901 is about 26842.5390192508. The cubic root of 720521901 is about 896.4974571569.

Adding to 720521901 its reverse (109125027), we get a palindrome (829646928).

The spelling of 720521901 in words is "seven hundred twenty million, five hundred twenty-one thousand, nine hundred one".