28401421 has 2 divisors, whose sum is σ = 28401422. Its totient is φ = 28401420.

The previous prime is 28401419. The next prime is 28401427. The reversal of 28401421 is 12410482.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 28355625 + 45796 = 5325^2 + 214^2 .

It is a cyclic number.

It is not a de Polignac number, because 28401421 - 2¹ = 28401419 is a prime.

Together with 28401419, 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 = 28401392 and 28401401.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28401427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14200710 + 14200711.

It is an arithmetic number, because the mean of its divisors is an integer number (14200711).

Almost surely, 2^28401421 is an apocalyptic number.

It is an amenable number.

28401421 is a deficient number, since it is larger than the sum of its proper divisors (1).

28401421 is an equidigital number, since it uses as much as digits as its factorization.

28401421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 512, while the sum is 22.

The square root of 28401421 is about 5329.2983590713. The cubic root of 28401421 is about 305.1031488438.

The spelling of 28401421 in words is "twenty-eight million, four hundred one thousand, four hundred twenty-one".