1166521639 has 2 divisors, whose sum is σ = 1166521640. Its totient is φ = 1166521638.

The previous prime is 1166521637. The next prime is 1166521669. The reversal of 1166521639 is 9361256611.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1166521639 - 2¹ = 1166521637 is a prime.

Together with 1166521637, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1166521637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 583260819 + 583260820.

It is an arithmetic number, because the mean of its divisors is an integer number (583260820).

Almost surely, 2^1166521639 is an apocalyptic number.

1166521639 is a deficient number, since it is larger than the sum of its proper divisors (1).

1166521639 is an equidigital number, since it uses as much as digits as its factorization.

1166521639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 58320, while the sum is 40.

The square root of 1166521639 is about 34154.3794995605. The cubic root of 1166521639 is about 1052.6829765211.

The spelling of 1166521639 in words is "one billion, one hundred sixty-six million, five hundred twenty-one thousand, six hundred thirty-nine".