1639249919 has 4 divisors (see below), whose sum is σ = 1641907344. Its totient is φ = 1636592496.

The previous prime is 1639249901. The next prime is 1639249949. The reversal of 1639249919 is 9199429361.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1639249919 - 2¹² = 1639245823 is a prime.

It is a super-2 number, since 2×1639249919² = 5374280593883013122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1639249949) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1327787 + ... + 1329020.

It is an arithmetic number, because the mean of its divisors is an integer number (410476836).

Almost surely, 2^1639249919 is an apocalyptic number.

1639249919 is a deficient number, since it is larger than the sum of its proper divisors (2657425).

1639249919 is an equidigital number, since it uses as much as digits as its factorization.

1639249919 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2657424.

The product of its digits is 944784, while the sum is 53.

The square root of 1639249919 is about 40487.6514384324. The cubic root of 1639249919 is about 1179.0938938292.

The spelling of 1639249919 in words is "one billion, six hundred thirty-nine million, two hundred forty-nine thousand, nine hundred nineteen".