624799981 has 4 divisors (see below), whose sum is σ = 672861532. Its totient is φ = 576738432.

The previous prime is 624799979. The next prime is 624800017. The reversal of 624799981 is 189997426.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 189997426 = 2 ⋅94998713.

It can be written as a sum of positive squares in 2 ways, for example, as 203319081 + 421480900 = 14259^2 + 20530^2 .

It is a cyclic number.

It is not a de Polignac number, because 624799981 - 2¹ = 624799979 is a prime.

It is a super-2 number, since 2×624799981² = 780750032515200722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (624799921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24030756 + ... + 24030781.

It is an arithmetic number, because the mean of its divisors is an integer number (168215383).

Almost surely, 2^624799981 is an apocalyptic number.

It is an amenable number.

624799981 is a deficient number, since it is larger than the sum of its proper divisors (48061551).

624799981 is a wasteful number, since it uses less digits than its factorization.

624799981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48061550.

The product of its digits is 1959552, while the sum is 55.

The square root of 624799981 is about 24995.9992998880. Note that the first 3 decimals coincide. The cubic root of 624799981 is about 854.8967562259.

The spelling of 624799981 in words is "six hundred twenty-four million, seven hundred ninety-nine thousand, nine hundred eighty-one".