87755721 has 16 divisors (see below), whose sum is σ = 120434688. Its totient is φ = 56810000.

The previous prime is 87755671. The next prime is 87755743. The reversal of 87755721 is 12755778.

It is a cyclic number.

It is not a de Polignac number, because 87755721 - 2⁷ = 87755593 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (87755321) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16096 + ... + 20846.

It is an arithmetic number, because the mean of its divisors is an integer number (7527168).

Almost surely, 2^87755721 is an apocalyptic number.

It is an amenable number.

87755721 is a deficient number, since it is larger than the sum of its proper divisors (32678967).

87755721 is a wasteful number, since it uses less digits than its factorization.

87755721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4932.

The product of its digits is 137200, while the sum is 42.

The square root of 87755721 is about 9367.8023570099. The cubic root of 87755721 is about 444.3840672820.

The spelling of 87755721 in words is "eighty-seven million, seven hundred fifty-five thousand, seven hundred twenty-one".