621791 has 4 divisors (see below), whose sum is σ = 623832. Its totient is φ = 619752.

The previous prime is 621779. The next prime is 621799. The reversal of 621791 is 197126.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 197126 = 2 ⋅98563.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-621791 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 621791.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (621799) 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, 461 + ... + 1206.

It is an arithmetic number, because the mean of its divisors is an integer number (155958).

2⁶²¹⁷⁹¹ is an apocalyptic number.

621791 is a deficient number, since it is larger than the sum of its proper divisors (2041).

621791 is a wasteful number, since it uses less digits than its factorization.

621791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2040.

The product of its digits is 756, while the sum is 26.

The square root of 621791 is about 788.5372534002. The cubic root of 621791 is about 85.3522178393.

The spelling of 621791 in words is "six hundred twenty-one thousand, seven hundred ninety-one".