1631389 has 4 divisors (see below), whose sum is σ = 1637856. Its totient is φ = 1624924.

The previous prime is 1631369. The next prime is 1631407. The reversal of 1631389 is 9831361.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1631389 - 2⁷ = 1631261 is a prime.

It is a super-2 number, since 2×1631389² = 5322860138642, which contains 22 as substring.

It is a Duffinian number.

1631389 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 1631389.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1631309) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2839 + ... + 3364.

It is an arithmetic number, because the mean of its divisors is an integer number (409464).

2^1631389 is an apocalyptic number.

It is an amenable number.

1631389 is a deficient number, since it is larger than the sum of its proper divisors (6467).

1631389 is an equidigital number, since it uses as much as digits as its factorization.

1631389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6466.

The product of its digits is 3888, while the sum is 31.

The square root of 1631389 is about 1277.2583920257. The cubic root of 1631389 is about 117.7206116376.

The spelling of 1631389 in words is "one million, six hundred thirty-one thousand, three hundred eighty-nine".