621206640 has 240 divisors, whose sum is σ = 2164361472. Its totient is φ = 159584256.

The previous prime is 621206629. The next prime is 621206683. The reversal of 621206640 is 46602126.

It is a happy number.

621206640 is a `hidden beast` number, since 6 + 2 + 12 + 0 + 6 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

It is a congruent number.

It is an unprimeable number.

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 47 ways as a sum of consecutive naturals, for example, 2785569 + ... + 2785791.

Almost surely, 2^621206640 is an apocalyptic number.

621206640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 621206640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1082180736).

621206640 is an abundant number, since it is smaller than the sum of its proper divisors (1543154832).

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

621206640 is a wasteful number, since it uses less digits than its factorization.

621206640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 368 (or 359 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 621206640 is about 24924.0173326854. The cubic root of 621206640 is about 853.2547141653.

Adding to 621206640 its reverse (46602126), we get a palindrome (667808766).

The spelling of 621206640 in words is "six hundred twenty-one million, two hundred six thousand, six hundred forty".