971639 has 2 divisors, whose sum is σ = 971640. Its totient is φ = 971638.

The previous prime is 971591. The next prime is 971651. The reversal of 971639 is 936179.

It is a strong prime.

It is an emirp because it is prime and its reverse (936179) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-971639 is a prime.

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 971599 and 971608.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (971699) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 485819 + 485820.

It is an arithmetic number, because the mean of its divisors is an integer number (485820).

2⁹⁷¹⁶³⁹ is an apocalyptic number.

971639 is a deficient number, since it is larger than the sum of its proper divisors (1).

971639 is an equidigital number, since it uses as much as digits as its factorization.

971639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10206, while the sum is 35.

The square root of 971639 is about 985.7175051707. The cubic root of 971639 is about 99.0455526177.

The spelling of 971639 in words is "nine hundred seventy-one thousand, six hundred thirty-nine".