87721563 has 16 divisors (see below), whose sum is σ = 122492160. Its totient is φ = 55734624.

The previous prime is 87721541. The next prime is 87721573. The reversal of 87721563 is 36512778.

It is not a de Polignac number, because 87721563 - 2¹⁶ = 87656027 is a prime.

It is not an unprimeable number, because it can be changed into a prime (87721573) 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, 18048 + ... + 22386.

It is an arithmetic number, because the mean of its divisors is an integer number (7655760).

Almost surely, 2^87721563 is an apocalyptic number.

87721563 is a deficient number, since it is larger than the sum of its proper divisors (34770597).

87721563 is a wasteful number, since it uses less digits than its factorization.

87721563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4658.

The product of its digits is 70560, while the sum is 39.

The square root of 87721563 is about 9365.9790198356. The cubic root of 87721563 is about 444.3264025103.

The spelling of 87721563 in words is "eighty-seven million, seven hundred twenty-one thousand, five hundred sixty-three".