21401000 has 32 divisors (see below), whose sum is σ = 50080680. Its totient is φ = 8560000.

The previous prime is 21400997. The next prime is 21401047. The reversal of 21401000 is 10412.

It can be written as a sum of positive squares in 4 ways, for example, as 3541924 + 17859076 = 1882^2 + 4226^2 .

It is a Harshad number since it is a multiple of its sum of digits (8).

It is an unprimeable number.

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 in 7 ways as a sum of consecutive naturals, for example, 9701 + ... + 11700.

Almost surely, 2^21401000 is an apocalyptic number.

21401000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21401000 is an abundant number, since it is smaller than the sum of its proper divisors (28679680).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21401000 is a wasteful number, since it uses less digits than its factorization.

21401000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21422 (or 21408 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 8.

The square root of 21401000 is about 4626.1214856508. The cubic root of 21401000 is about 277.6374342905.

Adding to 21401000 its reverse (10412), we get a palindrome (21411412).

The spelling of 21401000 in words is "twenty-one million, four hundred one thousand".