621991441 has 4 divisors (see below), whose sum is σ = 632188084. Its totient is φ = 611794800.

The previous prime is 621991439. The next prime is 621991457. The reversal of 621991441 is 144199126.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 33686416 + 588305025 = 5804^2 + 24255^2 .

It is a cyclic number.

It is not a de Polignac number, because 621991441 - 2¹ = 621991439 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 621991441.

It is not an unprimeable number, because it can be changed into a prime (621991421) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5098230 + ... + 5098351.

It is an arithmetic number, because the mean of its divisors is an integer number (158047021).

Almost surely, 2^621991441 is an apocalyptic number.

621991441 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

It is an amenable number.

621991441 is a deficient number, since it is larger than the sum of its proper divisors (10196643).

621991441 is a wasteful number, since it uses less digits than its factorization.

621991441 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10196642.

The product of its digits is 15552, while the sum is 37.

The square root of 621991441 is about 24939.7562337726. The cubic root of 621991441 is about 853.6138825500.

The spelling of 621991441 in words is "six hundred twenty-one million, nine hundred ninety-one thousand, four hundred forty-one".