87143921 has 4 divisors (see below), whose sum is σ = 92270052. Its totient is φ = 82017792.

The previous prime is 87143897. The next prime is 87143957. The reversal of 87143921 is 12934178.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 38688400 + 48455521 = 6220^2 + 6961^2 .

It is a de Polignac number, because none of the positive numbers 2^k-87143921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (87143981) 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, 2563040 + ... + 2563073.

It is an arithmetic number, because the mean of its divisors is an integer number (23067513).

Almost surely, 2^87143921 is an apocalyptic number.

It is an amenable number.

87143921 is a deficient number, since it is larger than the sum of its proper divisors (5126131).

87143921 is a wasteful number, since it uses less digits than its factorization.

87143921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5126130.

The product of its digits is 12096, while the sum is 35.

The square root of 87143921 is about 9335.0908404793. The cubic root of 87143921 is about 443.3489650332.

The spelling of 87143921 in words is "eighty-seven million, one hundred forty-three thousand, nine hundred twenty-one".