621616647 has 4 divisors (see below), whose sum is σ = 828822200. Its totient is φ = 414411096.

The previous prime is 621616627. The next prime is 621616649. The reversal of 621616647 is 746616126.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 621616647 - 2¹⁰ = 621615623 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (621616649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 103602772 + ... + 103602777.

It is an arithmetic number, because the mean of its divisors is an integer number (207205550).

Almost surely, 2^621616647 is an apocalyptic number.

621616647 is a deficient number, since it is larger than the sum of its proper divisors (207205553).

621616647 is a wasteful number, since it uses less digits than its factorization.

621616647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 207205552.

The product of its digits is 72576, while the sum is 39.

The square root of 621616647 is about 24932.2411146692. The cubic root of 621616647 is about 853.4423937791.

The spelling of 621616647 in words is "six hundred twenty-one million, six hundred sixteen thousand, six hundred forty-seven".