21525244321 has 8 divisors (see below), whose sum is σ = 24614090624. Its totient is φ = 18439850880.

The previous prime is 21525244303. The next prime is 21525244361. The reversal of 21525244321 is 12344252512.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21525244321 - 2¹³ = 21525236129 is a prime.

It is a super-2 number, since 2×21525244321² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21525244361) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 849840 + ... + 874801.

It is an arithmetic number, because the mean of its divisors is an integer number (3076761328).

Almost surely, 2^21525244321 is an apocalyptic number.

It is an amenable number.

21525244321 is a deficient number, since it is larger than the sum of its proper divisors (3088846303).

21525244321 is a wasteful number, since it uses less digits than its factorization.

21525244321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1726431.

The product of its digits is 19200, while the sum is 31.

Adding to 21525244321 its reverse (12344252512), we get a palindrome (33869496833).

It can be divided in two parts, 21525 and 244321, that multiplied together give a palindrome (5259009525).

The spelling of 21525244321 in words is "twenty-one billion, five hundred twenty-five million, two hundred forty-four thousand, three hundred twenty-one".