87141721 has 2 divisors, whose sum is σ = 87141722. Its totient is φ = 87141720.

The previous prime is 87141701. The next prime is 87141749. The reversal of 87141721 is 12714178.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 49491225 + 37650496 = 7035^2 + 6136^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-87141721 is a prime.

It is not a weakly prime, because it can be changed into another prime (87141701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43570860 + 43570861.

It is an arithmetic number, because the mean of its divisors is an integer number (43570861).

Almost surely, 2^87141721 is an apocalyptic number.

It is an amenable number.

87141721 is a deficient number, since it is larger than the sum of its proper divisors (1).

87141721 is an equidigital number, since it uses as much as digits as its factorization.

87141721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3136, while the sum is 31.

The square root of 87141721 is about 9334.9730047815. The cubic root of 87141721 is about 443.3452341326.

Adding to 87141721 its reverse (12714178), we get a palindrome (99855899).

The spelling of 87141721 in words is "eighty-seven million, one hundred forty-one thousand, seven hundred twenty-one".