621621009 has 6 divisors (see below), whose sum is σ = 897897026. Its totient is φ = 414414000.

The previous prime is 621620999. The next prime is 621621037. The reversal of 621621009 is 900126126.

It can be written as a sum of positive squares in only one way, i.e., 588305025 + 33315984 = 24255^2 + 5772^2 .

It is not a de Polignac number, because 621621009 - 2⁹ = 621620497 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (621621079) 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 5 ways as a sum of consecutive naturals, for example, 34534492 + ... + 34534509.

Almost surely, 2^621621009 is an apocalyptic number.

It is an amenable number.

621621009 is a deficient number, since it is larger than the sum of its proper divisors (276276017).

621621009 is a wasteful number, since it uses less digits than its factorization.

621621009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69069007 (or 69069004 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 621621009 is about 24932.3285916097. The cubic root of 621621009 is about 853.4443900293. Note that the first 3 decimals are identical.

It can be divided in two parts, 6216 and 21009, that added together give a square (27225 = 165²).

The spelling of 621621009 in words is "six hundred twenty-one million, six hundred twenty-one thousand, nine".