21234201261 has 16 divisors (see below), whose sum is σ = 34845869184. Its totient is φ = 11200457664.

The previous prime is 21234201221. The next prime is 21234201269. The reversal of 21234201261 is 16210243212.

It is not a de Polignac number, because 21234201261 - 2¹⁹ = 21233676973 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21234201269) 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 15 ways as a sum of consecutive naturals, for example, 38890206 + ... + 38890751.

It is an arithmetic number, because the mean of its divisors is an integer number (2177866824).

Almost surely, 2^21234201261 is an apocalyptic number.

21234201261 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21234201261 is a deficient number, since it is larger than the sum of its proper divisors (13611667923).

21234201261 is a wasteful number, since it uses less digits than its factorization.

21234201261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77780980.

The product of its (nonzero) digits is 1152, while the sum is 24.

Adding to 21234201261 its reverse (16210243212), we get a palindrome (37444444473).

The spelling of 21234201261 in words is "twenty-one billion, two hundred thirty-four million, two hundred one thousand, two hundred sixty-one".