13400921 has 2 divisors, whose sum is σ = 13400922. Its totient is φ = 13400920.

The previous prime is 13400903. The next prime is 13400923. The reversal of 13400921 is 12900431.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13249600 + 151321 = 3640^2 + 389^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-13400921 is a prime.

Together with 13400923, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 13400893 and 13400902.

It is not a weakly prime, because it can be changed into another prime (13400923) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6700460 + 6700461.

It is an arithmetic number, because the mean of its divisors is an integer number (6700461).

Almost surely, 2^13400921 is an apocalyptic number.

It is an amenable number.

13400921 is a deficient number, since it is larger than the sum of its proper divisors (1).

13400921 is an equidigital number, since it uses as much as digits as its factorization.

13400921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 13400921 is about 3660.7268403966. The cubic root of 13400921 is about 237.5262153888.

The spelling of 13400921 in words is "thirteen million, four hundred thousand, nine hundred twenty-one".