249610021 has 2 divisors, whose sum is σ = 249610022. Its totient is φ = 249610020.

The previous prime is 249610013. The next prime is 249610043. The reversal of 249610021 is 120016942.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 180902500 + 68707521 = 13450^2 + 8289^2 .

It is a cyclic number.

It is not a de Polignac number, because 249610021 - 2³ = 249610013 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (249610121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 124805010 + 124805011.

It is an arithmetic number, because the mean of its divisors is an integer number (124805011).

Almost surely, 2^249610021 is an apocalyptic number.

It is an amenable number.

249610021 is a deficient number, since it is larger than the sum of its proper divisors (1).

249610021 is an equidigital number, since it uses as much as digits as its factorization.

249610021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 249610021 is about 15799.0512689845. The cubic root of 249610021 is about 629.6327926426.

Adding to 249610021 its reverse (120016942), we get a palindrome (369626963).

The spelling of 249610021 in words is "two hundred forty-nine million, six hundred ten thousand, twenty-one".