1281890897 has 4 divisors (see below), whose sum is σ = 1465018176. Its totient is φ = 1098763620.

The previous prime is 1281890891. The next prime is 1281890921. The reversal of 1281890897 is 7980981821.

It is a happy number.

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: 7980981821 = 229 ⋅34851449.

It is a cyclic number.

It is not a de Polignac number, because 1281890897 - 2⁴ = 1281890881 is a prime.

It is a super-2 number, since 2×1281890897² = 3286488543622929218, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1281890891) 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, 91563629 + ... + 91563642.

It is an arithmetic number, because the mean of its divisors is an integer number (366254544).

Almost surely, 2^1281890897 is an apocalyptic number.

It is an amenable number.

1281890897 is a deficient number, since it is larger than the sum of its proper divisors (183127279).

1281890897 is an equidigital number, since it uses as much as digits as its factorization.

1281890897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 183127278.

The product of its (nonzero) digits is 580608, while the sum is 53.

The square root of 1281890897 is about 35803.5039765663. The cubic root of 1281890897 is about 1086.3014381753.

The spelling of 1281890897 in words is "one billion, two hundred eighty-one million, eight hundred ninety thousand, eight hundred ninety-seven".