11921001 has 16 divisors (see below), whose sum is σ = 16536960. Its totient is φ = 7629440.

The previous prime is 11920991. The next prime is 11921017. The reversal of 11921001 is 10012911.

It is a 3-Lehmer number, since φ(11921001) divides (11921001-1)³.

It is a cyclic number.

It is a Carmichael number.

It is not a de Polignac number, because 11921001 - 2²³ = 3532393 is a prime.

It is a super-2 number, since 2×11921001² = 284220529684002, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (11921051) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22621 + ... + 23141.

It is an arithmetic number, because the mean of its divisors is an integer number (1033560).

It is a Poulet number, since it divides 2^11921000-1.

Almost surely, 2^11921001 is an apocalyptic number.

It is an amenable number.

11921001 is a deficient number, since it is larger than the sum of its proper divisors (4615959).

11921001 is a wasteful number, since it uses less digits than its factorization.

11921001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 816.

The product of its (nonzero) digits is 18, while the sum is 15.

The square root of 11921001 is about 3452.6802632158. The cubic root of 11921001 is about 228.4393459921.

Adding to 11921001 its reverse (10012911), we get a palindrome (21933912).

The spelling of 11921001 in words is "eleven million, nine hundred twenty-one thousand, one".