21002901 has 8 divisors (see below), whose sum is σ = 28341600. Its totient is φ = 13833072.

The previous prime is 21002899. The next prime is 21002911. The reversal of 21002901 is 10920012.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21002901 - 2¹ = 21002899 is a prime.

It is a super-2 number, since 2×21002901² = 882243700831602, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002911) 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 in 7 ways as a sum of consecutive naturals, for example, 41926 + ... + 42423.

It is an arithmetic number, because the mean of its divisors is an integer number (3542700).

Almost surely, 2^21002901 is an apocalyptic number.

It is an amenable number.

21002901 is a deficient number, since it is larger than the sum of its proper divisors (7338699).

21002901 is an equidigital number, since it uses as much as digits as its factorization.

21002901 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84435.

The product of its (nonzero) digits is 36, while the sum is 15.

The square root of 21002901 is about 4582.8922090750. The cubic root of 21002901 is about 275.9051212421.

Adding to 21002901 its reverse (10920012), we get a palindrome (31922913).

The spelling of 21002901 in words is "twenty-one million, two thousand, nine hundred one".