101521666 has 4 divisors (see below), whose sum is σ = 152282502. Its totient is φ = 50760832.

The previous prime is 101521649. The next prime is 101521669. The reversal of 101521666 is 666125101.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 666125101 = 211 ⋅3156991.

It can be written as a sum of positive squares in only one way, i.e., 57684025 + 43837641 = 7595^2 + 6621^2 .

It is not an unprimeable number, because it can be changed into a prime (101521669) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25380415 + ... + 25380418.

Almost surely, 2^101521666 is an apocalyptic number.

101521666 is a deficient number, since it is larger than the sum of its proper divisors (50760836).

101521666 is an equidigital number, since it uses as much as digits as its factorization.

101521666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50760835.

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 101521666 is about 10075.7960479557. The cubic root of 101521666 is about 466.5013576621.

Adding to 101521666 its reverse (666125101), we get a palindrome (767646767).

The spelling of 101521666 in words is "one hundred one million, five hundred twenty-one thousand, six hundred sixty-six".