87293721 has 4 divisors (see below), whose sum is σ = 116391632. Its totient is φ = 58195812.

The previous prime is 87293699. The next prime is 87293729. The reversal of 87293721 is 12739278.

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 not a de Polignac number, because 87293721 - 2⁹ = 87293209 is a prime.

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 87293721.

It is not an unprimeable number, because it can be changed into a prime (87293729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14548951 + ... + 14548956.

It is an arithmetic number, because the mean of its divisors is an integer number (29097908).

Almost surely, 2^87293721 is an apocalyptic number.

It is an amenable number.

87293721 is a deficient number, since it is larger than the sum of its proper divisors (29097911).

87293721 is a wasteful number, since it uses less digits than its factorization.

87293721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29097910.

The product of its digits is 42336, while the sum is 39.

The square root of 87293721 is about 9343.1108844967. The cubic root of 87293721 is about 443.6028578868.

The spelling of 87293721 in words is "eighty-seven million, two hundred ninety-three thousand, seven hundred twenty-one".