1639249949 has 2 divisors, whose sum is σ = 1639249950. Its totient is φ = 1639249948.

The previous prime is 1639249901. The next prime is 1639250021. The reversal of 1639249949 is 9499429361.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1628687449 + 10562500 = 40357^2 + 3250^2 .

It is an emirp because it is prime and its reverse (9499429361) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1639249949 - 2⁸ = 1639249693 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1639249894 and 1639249903.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1639249049) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 819624974 + 819624975.

It is an arithmetic number, because the mean of its divisors is an integer number (819624975).

Almost surely, 2^1639249949 is an apocalyptic number.

It is an amenable number.

1639249949 is a deficient number, since it is larger than the sum of its proper divisors (1).

1639249949 is an equidigital number, since it uses as much as digits as its factorization.

1639249949 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3779136, while the sum is 56.

The square root of 1639249949 is about 40487.6518089158. The cubic root of 1639249949 is about 1179.0939010221.

The spelling of 1639249949 in words is "one billion, six hundred thirty-nine million, two hundred forty-nine thousand, nine hundred forty-nine".