624778981 has 2 divisors, whose sum is σ = 624778982. Its totient is φ = 624778980.

The previous prime is 624778963. The next prime is 624779011. The reversal of 624778981 is 189877426.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 603930625 + 20848356 = 24575^2 + 4566^2 .

It is a cyclic number.

It is not a de Polignac number, because 624778981 - 2¹⁷ = 624647909 is a prime.

It is a super-2 number, since 2×624778981² = 780697550198796722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (624778901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 312389490 + 312389491.

It is an arithmetic number, because the mean of its divisors is an integer number (312389491).

Almost surely, 2^624778981 is an apocalyptic number.

It is an amenable number.

624778981 is a deficient number, since it is larger than the sum of its proper divisors (1).

624778981 is an equidigital number, since it uses as much as digits as its factorization.

624778981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1354752, while the sum is 52.

The square root of 624778981 is about 24995.5792291357. The cubic root of 624778981 is about 854.8871782097.

The spelling of 624778981 in words is "six hundred twenty-four million, seven hundred seventy-eight thousand, nine hundred eighty-one".