1631129897 has 4 divisors (see below), whose sum is σ = 1631510160. Its totient is φ = 1630749636.

The previous prime is 1631129887. The next prime is 1631129921. The reversal of 1631129897 is 7989211361.

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, and also an emirpimes, since its reverse is a distinct semiprime: 7989211361 = 53 ⋅150739837.

It is a cyclic number.

It is not a de Polignac number, because 1631129897 - 2⁸ = 1631129641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1631129887) 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, 183623 + ... + 192300.

It is an arithmetic number, because the mean of its divisors is an integer number (407877540).

Almost surely, 2^1631129897 is an apocalyptic number.

It is an amenable number.

1631129897 is a deficient number, since it is larger than the sum of its proper divisors (380263).

1631129897 is an equidigital number, since it uses as much as digits as its factorization.

1631129897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 380262.

The product of its digits is 163296, while the sum is 47.

The square root of 1631129897 is about 40387.2491883268. The cubic root of 1631129897 is about 1177.1437903899.

The spelling of 1631129897 in words is "one billion, six hundred thirty-one million, one hundred twenty-nine thousand, eight hundred ninety-seven".