720621540 has 36 divisors (see below), whose sum is σ = 2185885884. Its totient is φ = 192165696.

The previous prime is 720621463. The next prime is 720621553. The reversal of 720621540 is 45126027.

It can be written as a sum of positive squares in 2 ways, for example, as 544475556 + 176145984 = 23334^2 + 13272^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2001547 + ... + 2001906.

Almost surely, 2^720621540 is an apocalyptic number.

It is an amenable number.

720621540 is an abundant number, since it is smaller than the sum of its proper divisors (1465264344).

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

720621540 is a wasteful number, since it uses less digits than its factorization.

720621540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4003468 (or 4003463 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 27.

The square root of 720621540 is about 26844.3949456865. The cubic root of 720621540 is about 896.5387799780.

Adding to 720621540 its reverse (45126027), we get a palindrome (765747567).

The spelling of 720621540 in words is "seven hundred twenty million, six hundred twenty-one thousand, five hundred forty".