21401075 has 6 divisors (see below), whose sum is σ = 26537364. Its totient is φ = 17120840.

The previous prime is 21401071. The next prime is 21401089. The reversal of 21401075 is 57010412.

It is not a de Polignac number, because 21401075 - 2² = 21401071 is a prime.

It is a super-2 number, since 2×21401075² = 916012022311250, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21401071) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 427997 + ... + 428046.

It is an arithmetic number, because the mean of its divisors is an integer number (4422894).

Almost surely, 2^21401075 is an apocalyptic number.

21401075 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21401075 is a deficient number, since it is larger than the sum of its proper divisors (5136289).

21401075 is an equidigital number, since it uses as much as digits as its factorization.

21401075 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 856053 (or 856048 counting only the distinct ones).

The product of its (nonzero) digits is 280, while the sum is 20.

The square root of 21401075 is about 4626.1295917862. The cubic root of 21401075 is about 277.6377586177.

Adding to 21401075 its reverse (57010412), we get a palindrome (78411487).

The spelling of 21401075 in words is "twenty-one million, four hundred one thousand, seventy-five".