621297809 has 16 divisors (see below), whose sum is σ = 684391680. Its totient is φ = 559334160.

The previous prime is 621297773. The next prime is 621297851. The reversal of 621297809 is 908792126.

It is a happy number.

It is not a de Polignac number, because 621297809 - 2¹⁶ = 621232273 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 621297809.

It is not an unprimeable number, because it can be changed into a prime (621297869) 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, 750854 + ... + 751680.

It is an arithmetic number, because the mean of its divisors is an integer number (42774480).

Almost surely, 2^621297809 is an apocalyptic number.

It is an amenable number.

621297809 is a deficient number, since it is larger than the sum of its proper divisors (63093871).

621297809 is a wasteful number, since it uses less digits than its factorization.

621297809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1420.

The product of its (nonzero) digits is 108864, while the sum is 44.

The square root of 621297809 is about 24925.8462042916. The cubic root of 621297809 is about 853.2964536708.

The spelling of 621297809 in words is "six hundred twenty-one million, two hundred ninety-seven thousand, eight hundred nine".