21522110421 has 32 divisors (see below), whose sum is σ = 33571749888. Its totient is φ = 12008517120.

The previous prime is 21522110371. The next prime is 21522110429. The reversal of 21522110421 is 12401122512.

It is not a de Polignac number, because 21522110421 - 2¹³ = 21522102229 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21522110429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 400101 + ... + 450693.

It is an arithmetic number, because the mean of its divisors is an integer number (1049117184).

Almost surely, 2^21522110421 is an apocalyptic number.

21522110421 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21522110421 is a deficient number, since it is larger than the sum of its proper divisors (12049639467).

21522110421 is a wasteful number, since it uses less digits than its factorization.

21522110421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51081.

The product of its (nonzero) digits is 320, while the sum is 21.

Adding to 21522110421 its reverse (12401122512), we get a palindrome (33923232933).

The spelling of 21522110421 in words is "twenty-one billion, five hundred twenty-two million, one hundred ten thousand, four hundred twenty-one".