21153251361 has 16 divisors (see below), whose sum is σ = 32387754240. Its totient is φ = 12145407120.

The previous prime is 21153251359. The next prime is 21153251387. The reversal of 21153251361 is 16315235112.

It is not a de Polignac number, because 21153251361 - 2¹ = 21153251359 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21153250361) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16867995 + ... + 16869248.

It is an arithmetic number, because the mean of its divisors is an integer number (2024234640).

Almost surely, 2^21153251361 is an apocalyptic number.

It is an amenable number.

21153251361 is a deficient number, since it is larger than the sum of its proper divisors (11234502879).

21153251361 is a wasteful number, since it uses less digits than its factorization.

21153251361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33737276.

The product of its digits is 5400, while the sum is 30.

Adding to 21153251361 its reverse (16315235112), we get a palindrome (37468486473).

The spelling of 21153251361 in words is "twenty-one billion, one hundred fifty-three million, two hundred fifty-one thousand, three hundred sixty-one".