21126163501 has 4 divisors (see below), whose sum is σ = 21280369212. Its totient is φ = 20971957792.

The previous prime is 21126163463. The next prime is 21126163523. The reversal of 21126163501 is 10536162112.

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

It can be written as a sum of positive squares in 2 ways, for example, as 12949302025 + 8176861476 = 113795^2 + 90426^2 .

It is a cyclic number.

It is not a de Polignac number, because 21126163501 - 2¹⁵ = 21126130733 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21126163501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21126163561) 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, 77102650 + ... + 77102923.

It is an arithmetic number, because the mean of its divisors is an integer number (5320092303).

Almost surely, 2^21126163501 is an apocalyptic number.

It is an amenable number.

21126163501 is a deficient number, since it is larger than the sum of its proper divisors (154205711).

21126163501 is a wasteful number, since it uses less digits than its factorization.

21126163501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154205710.

The product of its (nonzero) digits is 2160, while the sum is 28.

The spelling of 21126163501 in words is "twenty-one billion, one hundred twenty-six million, one hundred sixty-three thousand, five hundred one".