21525171131371 has 4 divisors (see below), whose sum is σ = 21554298562600. Its totient is φ = 21496043700144.

The previous prime is 21525171131327. The next prime is 21525171131423. The reversal of 21525171131371 is 17313117152512.

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 21525171131371 - 2¹⁵ = 21525171098603 is a prime.

It is a super-2 number, since 2×21525171131371² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21525171131671) 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, 14563714506 + ... + 14563715983.

It is an arithmetic number, because the mean of its divisors is an integer number (5388574640650).

Almost surely, 2^{21525171131371} is an apocalyptic number.

21525171131371 is a deficient number, since it is larger than the sum of its proper divisors (29127431229).

21525171131371 is an equidigital number, since it uses as much as digits as its factorization.

21525171131371 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29127431228.

The product of its digits is 44100, while the sum is 40.

Adding to 21525171131371 its reverse (17313117152512), we get a palindrome (38838288283883).

The spelling of 21525171131371 in words is "twenty-one trillion, five hundred twenty-five billion, one hundred seventy-one million, one hundred thirty-one thousand, three hundred seventy-one".