621728019 has 24 divisors (see below), whose sum is σ = 1022291712. Its totient is φ = 360420720.

The previous prime is 621727991. The next prime is 621728087. The reversal of 621728019 is 910827126.

621728019 is a `hidden beast` number, since 621 + 7 + 28 + 0 + 1 + 9 = 666.

It is not a de Polignac number, because 621728019 - 2⁵ = 621727987 is a prime.

It is a super-2 number, since 2×621728019² = 773091459219328722, which contains 22 as substring.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (621728519) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 134247 + ... + 138800.

It is an arithmetic number, because the mean of its divisors is an integer number (42595488).

Almost surely, 2^621728019 is an apocalyptic number.

621728019 is a gapful number since it is divisible by the number (69) formed by its first and last digit.

621728019 is a deficient number, since it is larger than the sum of its proper divisors (400563693).

621728019 is a wasteful number, since it uses less digits than its factorization.

621728019 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 273087 (or 273084 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 36.

The square root of 621728019 is about 24934.4745081985. The cubic root of 621728019 is about 853.4933597621.

The spelling of 621728019 in words is "six hundred twenty-one million, seven hundred twenty-eight thousand, nineteen".