21013101 has 10 divisors (see below), whose sum is σ = 31390062. Its totient is φ = 14008680.

The previous prime is 21013093. The next prime is 21013103. The reversal of 21013101 is 10131012.

It can be written as a sum of positive squares in only one way, i.e., 19448100 + 1565001 = 4410^2 + 1251^2 .

It is not a de Polignac number, because 21013101 - 2³ = 21013093 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 (21013103) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 129630 + ... + 129791.

Almost surely, 2^21013101 is an apocalyptic number.

It is an amenable number.

21013101 is a deficient number, since it is larger than the sum of its proper divisors (10376961).

21013101 is an equidigital number, since it uses as much as digits as its factorization.

21013101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 259433 (or 259424 counting only the distinct ones).

The product of its (nonzero) digits is 6, while the sum is 9.

The square root of 21013101 is about 4584.0049083743. The cubic root of 21013101 is about 275.9497781966.

Adding to 21013101 its reverse (10131012), we get a palindrome (31144113).

It can be divided in two parts, 2 and 1013101, that multiplied together give a palindrome (2026202).

The spelling of 21013101 in words is "twenty-one million, thirteen thousand, one hundred one".