621780 has 48 divisors (see below), whose sum is σ = 1788864. Its totient is φ = 161280.

The previous prime is 621779. The next prime is 621799. The reversal of 621780 is 87126.

It is a super-2 number, since 2×621780² = 773220736800, which contains 22 as substring.

It is a hoax number, since the sum of its digits (24) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 621780.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2460 + ... + 2700.

It is an arithmetic number, because the mean of its divisors is an integer number (37268).

2⁶²¹⁷⁸⁰ is an apocalyptic number.

621780 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 621780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (894432).

621780 is an abundant number, since it is smaller than the sum of its proper divisors (1167084).

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

621780 is a wasteful number, since it uses less digits than its factorization.

621780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 296 (or 294 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 621780 is about 788.5302784294. The cubic root of 621780 is about 85.3517145191.

The spelling of 621780 in words is "six hundred twenty-one thousand, seven hundred eighty".