621881 has 4 divisors (see below), whose sum is σ = 669732. Its totient is φ = 574032.

The previous prime is 621871. The next prime is 621883. The reversal of 621881 is 188126.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 188126 = 2 ⋅94063.

It can be written as a sum of positive squares in 2 ways, for example, as 144400 + 477481 = 380^2 + 691^2 .

It is a cyclic number.

It is not a de Polignac number, because 621881 - 2¹⁴ = 605497 is a prime.

It is a super-2 number, since 2×621881² = 773471956322, which contains 22 as substring.

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 621881.

It is not an unprimeable number, because it can be changed into a prime (621883) 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, 23906 + ... + 23931.

It is an arithmetic number, because the mean of its divisors is an integer number (167433).

2⁶²¹⁸⁸¹ is an apocalyptic number.

It is an amenable number.

621881 is a deficient number, since it is larger than the sum of its proper divisors (47851).

621881 is a wasteful number, since it uses less digits than its factorization.

621881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47850.

The product of its digits is 768, while the sum is 26.

The square root of 621881 is about 788.5943190259. The cubic root of 621881 is about 85.3563356908.

The spelling of 621881 in words is "six hundred twenty-one thousand, eight hundred eighty-one".