21231352501 has 4 divisors (see below), whose sum is σ = 21306375232. Its totient is φ = 21156329772.

The previous prime is 21231352489. The next prime is 21231352517. The reversal of 21231352501 is 10525313212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21231352501 - 2²⁹ = 20694481589 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21231352561) 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, 37510941 + ... + 37511506.

It is an arithmetic number, because the mean of its divisors is an integer number (5326593808).

Almost surely, 2^21231352501 is an apocalyptic number.

It is an amenable number.

21231352501 is a deficient number, since it is larger than the sum of its proper divisors (75022731).

21231352501 is an equidigital number, since it uses as much as digits as its factorization.

21231352501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75022730.

The product of its (nonzero) digits is 1800, while the sum is 25.

Adding to 21231352501 its reverse (10525313212), we get a palindrome (31756665713).

The spelling of 21231352501 in words is "twenty-one billion, two hundred thirty-one million, three hundred fifty-two thousand, five hundred one".