621987840 has 288 divisors, whose sum is σ = 2288253240. Its totient is φ = 155713536.

The previous prime is 621987811. The next prime is 621987841. The reversal of 621987840 is 48789126.

It can be written as a sum of positive squares in 4 ways, for example, as 589906944 + 32080896 = 24288^2 + 5664^2 .

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (621987841) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1566522 + ... + 1566918.

Almost surely, 2^621987840 is an apocalyptic number.

621987840 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 621987840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1144126620).

621987840 is an abundant number, since it is smaller than the sum of its proper divisors (1666265400).

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

621987840 is a wasteful number, since it uses less digits than its factorization.

621987840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 447 (or 424 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 45.

The square root of 621987840 is about 24939.6840396987. The cubic root of 621987840 is about 853.6122352232.

The spelling of 621987840 in words is "six hundred twenty-one million, nine hundred eighty-seven thousand, eight hundred forty".