21220054149529 has 9 divisors (see below), whose sum is σ = 21257871788127. Its totient is φ = 21182303693544.

The previous prime is 21220054149527. The next prime is 21220054149533. The reversal of 21220054149529 is 92594145002212.

It is a happy number.

The square root of 21220054149529 is 4606523.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 273138981129 + 20946915168400 = 522627^2 + 4576780^2 .

It is not a de Polignac number, because 21220054149529 - 2¹ = 21220054149527 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21220054149527) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 2796155667 + ... + 2796163255.

Almost surely, 2^{21220054149529} is an apocalyptic number.

21220054149529 is the 4606523-rd square number.

21220054149529 is the 2303262-nd centered octagonal number.

It is an amenable number.

21220054149529 is a deficient number, since it is larger than the sum of its proper divisors (37817638598).

21220054149529 is an frugal number, since it uses more digits than its factorization.

21220054149529 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16392 (or 8196 counting only the distinct ones).

The product of its (nonzero) digits is 518400, while the sum is 46.

The spelling of 21220054149529 in words is "twenty-one trillion, two hundred twenty billion, fifty-four million, one hundred forty-nine thousand, five hundred twenty-nine".