13945011921 has 15 divisors (see below), whose sum is σ = 20833025323. Its totient is φ = 9295966080.

The previous prime is 13945011919. The next prime is 13945011931. The reversal of 13945011921 is 12911054931.

The square root of 13945011921 is 118089.

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

13945011921 is a `hidden beast` number, since 13 + 9 + 450 + 1 + 192 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1967898321 + 11977113600 = 44361^2 + 109440^2 .

It is not a de Polignac number, because 13945011921 - 2¹ = 13945011919 is a prime.

It is a super-2 number, since 2×13945011921² (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 (13945011911) by changing a digit.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 1056241 + ... + 1069361.

Almost surely, 2^13945011921 is an apocalyptic number.

13945011921 is the 118089-th square number.

13945011921 is the 59045-th centered octagonal number.

It is an amenable number.

13945011921 is a deficient number, since it is larger than the sum of its proper divisors (6888013402).

13945011921 is an frugal number, since it uses more digits than its factorization.

13945011921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26254 (or 13124 counting only the distinct ones).

The product of its (nonzero) digits is 9720, while the sum is 36.

Multiplying 13945011921 by its sum of digits (36), we get a square (502020429156 = 708534²).

The spelling of 13945011921 in words is "thirteen billion, nine hundred forty-five million, eleven thousand, nine hundred twenty-one".