2499781 has 2 divisors, whose sum is σ = 2499782. Its totient is φ = 2499780.

The previous prime is 2499779. The next prime is 2499793. The reversal of 2499781 is 1879942.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1416100 + 1083681 = 1190^2 + 1041^2 .

It is a cyclic number.

It is not a de Polignac number, because 2499781 - 2¹ = 2499779 is a prime.

It is a super-2 number, since 2×2499781² = 12497810095922, which contains 22 as substring.

Together with 2499779, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2499751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1249890 + 1249891.

It is an arithmetic number, because the mean of its divisors is an integer number (1249891).

2^2499781 is an apocalyptic number.

It is an amenable number.

2499781 is a deficient number, since it is larger than the sum of its proper divisors (1).

2499781 is an equidigital number, since it uses as much as digits as its factorization.

2499781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36288, while the sum is 40.

The square root of 2499781 is about 1581.0695746867. The cubic root of 2499781 is about 135.7169176643.

The spelling of 2499781 in words is "two million, four hundred ninety-nine thousand, seven hundred eighty-one".