1639249901 has 2 divisors, whose sum is σ = 1639249902. Its totient is φ = 1639249900.

The previous prime is 1639249847. The next prime is 1639249949. The reversal of 1639249901 is 1099429361.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1270993801 + 368256100 = 35651^2 + 19190^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1639249901 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1639245901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 819624950 + 819624951.

It is an arithmetic number, because the mean of its divisors is an integer number (819624951).

Almost surely, 2^1639249901 is an apocalyptic number.

It is an amenable number.

1639249901 is a deficient number, since it is larger than the sum of its proper divisors (1).

1639249901 is an equidigital number, since it uses as much as digits as its factorization.

1639249901 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 104976, while the sum is 44.

The square root of 1639249901 is about 40487.6512161424. The cubic root of 1639249901 is about 1179.0938895135.

The spelling of 1639249901 in words is "one billion, six hundred thirty-nine million, two hundred forty-nine thousand, nine hundred one".