87390721 has 8 divisors (see below), whose sum is σ = 97661088. Its totient is φ = 77508000.

The previous prime is 87390701. The next prime is 87390757. The reversal of 87390721 is 12709378.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 87390721 - 2¹¹ = 87388673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (87390701) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 96435 + ... + 97336.

It is an arithmetic number, because the mean of its divisors is an integer number (12207636).

Almost surely, 2^87390721 is an apocalyptic number.

It is an amenable number.

87390721 is a deficient number, since it is larger than the sum of its proper divisors (10270367).

87390721 is a wasteful number, since it uses less digits than its factorization.

87390721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 193823.

The product of its (nonzero) digits is 21168, while the sum is 37.

The square root of 87390721 is about 9348.3004337687. The cubic root of 87390721 is about 443.7671062373.

The spelling of 87390721 in words is "eighty-seven million, three hundred ninety thousand, seven hundred twenty-one".