621720517 has 16 divisors (see below), whose sum is σ = 689762304. Its totient is φ = 555646000.

The previous prime is 621720511. The next prime is 621720551. The reversal of 621720517 is 715027126.

621720517 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 621720517 - 2⁷ = 621720389 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (621720511) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 335688 + ... + 337534.

It is an arithmetic number, because the mean of its divisors is an integer number (43110144).

Almost surely, 2^621720517 is an apocalyptic number.

It is an amenable number.

621720517 is a deficient number, since it is larger than the sum of its proper divisors (68041787).

621720517 is a wasteful number, since it uses less digits than its factorization.

621720517 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2360.

The product of its (nonzero) digits is 5880, while the sum is 31.

The square root of 621720517 is about 24934.3240734534. The cubic root of 621720517 is about 853.4899268929.

The spelling of 621720517 in words is "six hundred twenty-one million, seven hundred twenty thousand, five hundred seventeen".