21241651 has 4 divisors (see below), whose sum is σ = 21281032. Its totient is φ = 21202272.

The previous prime is 21241643. The next prime is 21241667. The reversal of 21241651 is 15614212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21241651 - 2³ = 21241643 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21241631) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18870 + ... + 19963.

It is an arithmetic number, because the mean of its divisors is an integer number (5320258).

Almost surely, 2^21241651 is an apocalyptic number.

21241651 is a deficient number, since it is larger than the sum of its proper divisors (39381).

21241651 is an equidigital number, since it uses as much as digits as its factorization.

21241651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39380.

The product of its digits is 480, while the sum is 22.

The square root of 21241651 is about 4608.8665634839. The cubic root of 21241651 is about 276.9466331002.

Adding to 21241651 its reverse (15614212), we get a palindrome (36855863).

The spelling of 21241651 in words is "twenty-one million, two hundred forty-one thousand, six hundred fifty-one".