1638129490 has 32 divisors (see below), whose sum is σ = 3069860400. Its totient is φ = 628798464.

The previous prime is 1638129487. The next prime is 1638129491. The reversal of 1638129490 is 949218361.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 1429066809 + 209062681 = 37803^2 + 14459^2 .

It is an alternating number because its digits alternate between odd and even.

It is not an unprimeable number, because it can be changed into a prime (1638129491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3315 + ... + 57334.

Almost surely, 2^1638129490 is an apocalyptic number.

1638129490 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1638129490 is a deficient number, since it is larger than the sum of its proper divisors (1431730910).

1638129490 is a wasteful number, since it uses less digits than its factorization.

1638129490 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60766.

The product of its (nonzero) digits is 93312, while the sum is 43.

The square root of 1638129490 is about 40473.8123976479. The cubic root of 1638129490 is about 1178.8251953063.

The spelling of 1638129490 in words is "one billion, six hundred thirty-eight million, one hundred twenty-nine thousand, four hundred ninety".