87521761 has 8 divisors (see below), whose sum is σ = 90155304. Its totient is φ = 84902400.

The previous prime is 87521747. The next prime is 87521779. The reversal of 87521761 is 16712578.

It can be written as a sum of positive squares in 4 ways, for example, as 21911761 + 65610000 = 4681^2 + 8100^2 .

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 87521761 - 2⁷ = 87521633 is a prime.

It is a super-2 number, since 2×87521761² = 15320117297082242, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (37).

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 87521761.

It is not an unprimeable number, because it can be changed into a prime (87521701) 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, 9711 + ... + 16411.

It is an arithmetic number, because the mean of its divisors is an integer number (11269413).

Almost surely, 2^87521761 is an apocalyptic number.

It is an amenable number.

87521761 is a deficient number, since it is larger than the sum of its proper divisors (2633543).

87521761 is a wasteful number, since it uses less digits than its factorization.

87521761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7091.

The product of its digits is 23520, while the sum is 37.

The square root of 87521761 is about 9355.3065690014. The cubic root of 87521761 is about 443.9888010188.

The spelling of 87521761 in words is "eighty-seven million, five hundred twenty-one thousand, seven hundred sixty-one".