21272120454 has 64 divisors (see below), whose sum is σ = 47763652608. Its totient is φ = 6271344000.

The previous prime is 21272120449. The next prime is 21272120497. The reversal of 21272120454 is 45402127212.

It is a super-2 number, since 2×21272120454² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 200667 + ... + 287769.

It is an arithmetic number, because the mean of its divisors is an integer number (746307072).

Almost surely, 2^21272120454 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21272120454, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23881826304).

21272120454 is an abundant number, since it is smaller than the sum of its proper divisors (26491532154).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21272120454 is a wasteful number, since it uses less digits than its factorization.

21272120454 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87253.

The product of its (nonzero) digits is 8960, while the sum is 30.

Adding to 21272120454 its reverse (45402127212), we get a palindrome (66674247666).

The spelling of 21272120454 in words is "twenty-one billion, two hundred seventy-two million, one hundred twenty thousand, four hundred fifty-four".