21400801 has 2 divisors, whose sum is σ = 21400802. Its totient is φ = 21400800.

The previous prime is 21400793. The next prime is 21400823. The reversal of 21400801 is 10800412.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21150801 + 250000 = 4599^2 + 500^2 .

It is a cyclic number.

It is not a de Polignac number, because 21400801 - 2³ = 21400793 is a prime.

It is a super-3 number, since 3×21400801³ (a number of 23 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (21400831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10700400 + 10700401.

It is an arithmetic number, because the mean of its divisors is an integer number (10700401).

Almost surely, 2^21400801 is an apocalyptic number.

It is an amenable number.

21400801 is a deficient number, since it is larger than the sum of its proper divisors (1).

21400801 is an equidigital number, since it uses as much as digits as its factorization.

21400801 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 64, while the sum is 16.

The square root of 21400801 is about 4626.0999773027. The cubic root of 21400801 is about 277.6365737385.

It can be divided in two parts, 21400 and 801, that added together give a square (22201 = 149²).

The spelling of 21400801 in words is "twenty-one million, four hundred thousand, eight hundred one".