166653881 has 2 divisors, whose sum is σ = 166653882. Its totient is φ = 166653880.

The previous prime is 166653863. The next prime is 166653887. The reversal of 166653881 is 188356661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 97614400 + 69039481 = 9880^2 + 8309^2 .

It is an emirp because it is prime and its reverse (188356661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 166653881 - 2¹⁸ = 166391737 is a prime.

It is a super-2 number, since 2×166653881² = 55547032104724322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (166653887) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83326940 + 83326941.

It is an arithmetic number, because the mean of its divisors is an integer number (83326941).

Almost surely, 2^166653881 is an apocalyptic number.

It is an amenable number.

166653881 is a deficient number, since it is larger than the sum of its proper divisors (1).

166653881 is an equidigital number, since it uses as much as digits as its factorization.

166653881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 207360, while the sum is 44.

The square root of 166653881 is about 12909.4492911201. The cubic root of 166653881 is about 550.3071353422.

The spelling of 166653881 in words is "one hundred sixty-six million, six hundred fifty-three thousand, eight hundred eighty-one".