21142351501 has 4 divisors (see below), whose sum is σ = 21142643004. Its totient is φ = 21142060000.

The previous prime is 21142351481. The next prime is 21142351561. The reversal of 21142351501 is 10515324112.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 3155518276 + 17986833225 = 56174^2 + 134115^2 .

It is a cyclic number.

It is not a de Polignac number, because 21142351501 - 2¹¹ = 21142349453 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 (21142351561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 57801 + ... + 213601.

It is an arithmetic number, because the mean of its divisors is an integer number (5285660751).

Almost surely, 2^21142351501 is an apocalyptic number.

It is an amenable number.

21142351501 is a deficient number, since it is larger than the sum of its proper divisors (291503).

21142351501 is a wasteful number, since it uses less digits than its factorization.

21142351501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 291502.

The product of its (nonzero) digits is 1200, while the sum is 25.

Adding to 21142351501 its reverse (10515324112), we get a palindrome (31657675613).

The spelling of 21142351501 in words is "twenty-one billion, one hundred forty-two million, three hundred fifty-one thousand, five hundred one".