101209921 has 2 divisors, whose sum is σ = 101209922. Its totient is φ = 101209920.

The previous prime is 101209907. The next prime is 101209937. The reversal of 101209921 is 129902101.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 100801600 + 408321 = 10040^2 + 639^2 .

It is a cyclic number.

It is not a de Polignac number, because 101209921 - 2¹⁷ = 101078849 is a prime.

It is not a weakly prime, because it can be changed into another prime (101209991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 50604960 + 50604961.

It is an arithmetic number, because the mean of its divisors is an integer number (50604961).

Almost surely, 2^101209921 is an apocalyptic number.

It is an amenable number.

101209921 is a deficient number, since it is larger than the sum of its proper divisors (1).

101209921 is an equidigital number, since it uses as much as digits as its factorization.

101209921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 324, while the sum is 25.

The square root of 101209921 is about 10060.3141601045. The cubic root of 101209921 is about 466.0233691241.

The spelling of 101209921 in words is "one hundred one million, two hundred nine thousand, nine hundred twenty-one".