87821137 has 2 divisors, whose sum is σ = 87821138. Its totient is φ = 87821136.

The previous prime is 87821101. The next prime is 87821141. The reversal of 87821137 is 73112878.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 47320641 + 40500496 = 6879^2 + 6364^2 .

It is a cyclic number.

It is not a de Polignac number, because 87821137 - 2⁷ = 87821009 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 87821096 and 87821105.

It is not a weakly prime, because it can be changed into another prime (87821177) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43910568 + 43910569.

It is an arithmetic number, because the mean of its divisors is an integer number (43910569).

Almost surely, 2^87821137 is an apocalyptic number.

It is an amenable number.

87821137 is a deficient number, since it is larger than the sum of its proper divisors (1).

87821137 is an equidigital number, since it uses as much as digits as its factorization.

87821137 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18816, while the sum is 37.

The square root of 87821137 is about 9371.2932405298. The cubic root of 87821137 is about 444.4944593552.

The spelling of 87821137 in words is "eighty-seven million, eight hundred twenty-one thousand, one hundred thirty-seven".