1987217853 has 4 divisors (see below), whose sum is σ = 2649623808. Its totient is φ = 1324811900.

The previous prime is 1987217851. The next prime is 1987217879. The reversal of 1987217853 is 3587127891.

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 1987217853 - 2¹ = 1987217851 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1987217796 and 1987217805.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1987217851) 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, 331202973 + ... + 331202978.

It is an arithmetic number, because the mean of its divisors is an integer number (662405952).

Almost surely, 2^1987217853 is an apocalyptic number.

It is an amenable number.

1987217853 is a deficient number, since it is larger than the sum of its proper divisors (662405955).

1987217853 is an equidigital number, since it uses as much as digits as its factorization.

1987217853 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 662405954.

The product of its digits is 846720, while the sum is 51.

The square root of 1987217853 is about 44578.2217343851. The cubic root of 1987217853 is about 1257.2312287709.

The spelling of 1987217853 in words is "one billion, nine hundred eighty-seven million, two hundred seventeen thousand, eight hundred fifty-three".