1897000561 has 4 divisors (see below), whose sum is σ = 1897280500. Its totient is φ = 1896720624.

The previous prime is 1897000549. The next prime is 1897000571. The reversal of 1897000561 is 1650007981.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1650007981 = 17 ⋅97059293.

It can be written as a sum of positive squares in 2 ways, for example, as 743107600 + 1153892961 = 27260^2 + 33969^2 .

It is a cyclic number.

It is not a de Polignac number, because 1897000561 - 2⁵ = 1897000529 is a prime.

It is a super-2 number, since 2×1897000561² = 7197222256868629442, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1897000561.

It is not an unprimeable number, because it can be changed into a prime (1897000531) 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, 129546 + ... + 143443.

It is an arithmetic number, because the mean of its divisors is an integer number (474320125).

Almost surely, 2^1897000561 is an apocalyptic number.

It is an amenable number.

1897000561 is a deficient number, since it is larger than the sum of its proper divisors (279939).

1897000561 is an equidigital number, since it uses as much as digits as its factorization.

1897000561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 279938.

The product of its (nonzero) digits is 15120, while the sum is 37.

The square root of 1897000561 is about 43554.5699209624. The cubic root of 1897000561 is about 1237.9102333556.

The spelling of 1897000561 in words is "one billion, eight hundred ninety-seven million, five hundred sixty-one", and thus it is an aban number.