721620612 has 18 divisors (see below), whose sum is σ = 1824096638. Its totient is φ = 240540192.

The previous prime is 721620611. The next prime is 721620637. The reversal of 721620612 is 216026127.

721620612 is a `hidden beast` number, since 7 + 21 + 6 + 20 + 612 = 666.

It can be written as a sum of positive squares in only one way, i.e., 472801536 + 248819076 = 21744^2 + 15774^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is not an unprimeable number, because it can be changed into a prime (721620611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 10022473 + ... + 10022544.

Almost surely, 2^721620612 is an apocalyptic number.

It is an amenable number.

721620612 is an abundant number, since it is smaller than the sum of its proper divisors (1102476026).

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

721620612 is a wasteful number, since it uses less digits than its factorization.

721620612 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20045027 (or 20045022 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 721620612 is about 26862.9970777648. The cubic root of 721620612 is about 896.9529100606.

Adding to 721620612 its reverse (216026127), we get a palindrome (937646739).

The spelling of 721620612 in words is "seven hundred twenty-one million, six hundred twenty thousand, six hundred twelve".