21054090145 has 24 divisors (see below), whose sum is σ = 27947527272. Its totient is φ = 15214467840.

The previous prime is 21054090143. The next prime is 21054090149. The reversal of 21054090145 is 54109045012.

It can be written as a sum of positive squares in 4 ways, for example, as 343138576 + 20710951569 = 18524^2 + 143913^2 .

It is not a de Polignac number, because 21054090145 - 2¹ = 21054090143 is a prime.

It is a super-2 number, since 2×21054090145² (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 (21054090143) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15844 + ... + 205813.

It is an arithmetic number, because the mean of its divisors is an integer number (1164480303).

Almost surely, 2^21054090145 is an apocalyptic number.

It is an amenable number.

21054090145 is a deficient number, since it is larger than the sum of its proper divisors (6893437127).

21054090145 is a wasteful number, since it uses less digits than its factorization.

21054090145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221841 (or 221830 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 31.

The spelling of 21054090145 in words is "twenty-one billion, fifty-four million, ninety thousand, one hundred forty-five".