87091973 has 2 divisors, whose sum is σ = 87091974. Its totient is φ = 87091972.

The previous prime is 87091943. The next prime is 87091999. The reversal of 87091973 is 37919078.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 75030244 + 12061729 = 8662^2 + 3473^2 .

It is a cyclic number.

It is not a de Polignac number, because 87091973 - 2⁸ = 87091717 is a prime.

It is a super-2 number, since 2×87091973² = 15170023522065458, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (87091943) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43545986 + 43545987.

It is an arithmetic number, because the mean of its divisors is an integer number (43545987).

Almost surely, 2^87091973 is an apocalyptic number.

It is an amenable number.

87091973 is a deficient number, since it is larger than the sum of its proper divisors (1).

87091973 is an equidigital number, since it uses as much as digits as its factorization.

87091973 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 95256, while the sum is 44.

The square root of 87091973 is about 9332.3080210632. The cubic root of 87091973 is about 443.2608515244.

The spelling of 87091973 in words is "eighty-seven million, ninety-one thousand, nine hundred seventy-three".