166121655 has 32 divisors (see below), whose sum is σ = 319756800. Its totient is φ = 71943552.

The previous prime is 166121633. The next prime is 166121689. The reversal of 166121655 is 556121661.

It is not a de Polignac number, because 166121655 - 2¹⁰ = 166120631 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 39640 + ... + 43629.

It is an arithmetic number, because the mean of its divisors is an integer number (9992400).

Almost surely, 2^166121655 is an apocalyptic number.

166121655 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

166121655 is a deficient number, since it is larger than the sum of its proper divisors (153635145).

166121655 is a wasteful number, since it uses less digits than its factorization.

166121655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83303.

The product of its digits is 10800, while the sum is 33.

The square root of 166121655 is about 12888.8189916687. The cubic root of 166121655 is about 549.7206901363.

The spelling of 166121655 in words is "one hundred sixty-six million, one hundred twenty-one thousand, six hundred fifty-five".