85731397 has 2 divisors, whose sum is σ = 85731398. Its totient is φ = 85731396.

The previous prime is 85731383. The next prime is 85731409. The reversal of 85731397 is 79313758.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 68707521 + 17023876 = 8289^2 + 4126^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-85731397 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (85731377) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42865698 + 42865699.

It is an arithmetic number, because the mean of its divisors is an integer number (42865699).

Almost surely, 2^85731397 is an apocalyptic number.

It is an amenable number.

85731397 is a deficient number, since it is larger than the sum of its proper divisors (1).

85731397 is an equidigital number, since it uses as much as digits as its factorization.

85731397 is an evil number, because the sum of its binary digits is even.

The product of its digits is 158760, while the sum is 43.

The square root of 85731397 is about 9259.1250666572. The cubic root of 85731397 is about 440.9404762980.

The spelling of 85731397 in words is "eighty-five million, seven hundred thirty-one thousand, three hundred ninety-seven".