21012201 has 24 divisors (see below), whose sum is σ = 35280960. Its totient is φ = 11801376.

The previous prime is 21012193. The next prime is 21012227. The reversal of 21012201 is 10221012.

It is not a de Polignac number, because 21012201 - 2³ = 21012193 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012241) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 891 + ... + 6543.

It is an arithmetic number, because the mean of its divisors is an integer number (1470040).

Almost surely, 2^21012201 is an apocalyptic number.

21012201 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21012201 is a deficient number, since it is larger than the sum of its proper divisors (14268759).

21012201 is a wasteful number, since it uses less digits than its factorization.

21012201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5725 (or 5722 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 21012201 is about 4583.9067398890. The cubic root of 21012201 is about 275.9458384585.

Adding to 21012201 its reverse (10221012), we get a palindrome (31233213).

The spelling of 21012201 in words is "twenty-one million, twelve thousand, two hundred one".