621213440 has 72 divisors (see below), whose sum is σ = 1552769568. Its totient is φ = 237670400.

The previous prime is 621213407. The next prime is 621213469. The reversal of 621213440 is 44312126.

621213440 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×621213440² = 771812276073267200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18890 + ... + 39990.

It is an arithmetic number, because the mean of its divisors is an integer number (21566244).

Almost surely, 2^621213440 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 621213440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (776384784).

621213440 is an abundant number, since it is smaller than the sum of its proper divisors (931556128).

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

621213440 is a wasteful number, since it uses less digits than its factorization.

621213440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21145 (or 21131 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 23.

The square root of 621213440 is about 24924.1537469179. The cubic root of 621213440 is about 853.2578275206.

Adding to 621213440 its reverse (44312126), we get a palindrome (665525566).

The spelling of 621213440 in words is "six hundred twenty-one million, two hundred thirteen thousand, four hundred forty".