21122120145 has 16 divisors (see below), whose sum is σ = 38623305600. Its totient is φ = 9655826304.

The previous prime is 21122120143. The next prime is 21122120179. The reversal of 21122120145 is 54102122112.

It is not a de Polignac number, because 21122120145 - 2¹ = 21122120143 is a prime.

It is a super-2 number, since 2×21122120145² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (21122120143) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 100581420 + ... + 100581629.

It is an arithmetic number, because the mean of its divisors is an integer number (2413956600).

Almost surely, 2^21122120145 is an apocalyptic number.

It is an amenable number.

21122120145 is a deficient number, since it is larger than the sum of its proper divisors (17501185455).

21122120145 is a wasteful number, since it uses less digits than its factorization.

21122120145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 201163064.

The product of its (nonzero) digits is 320, while the sum is 21.

Adding to 21122120145 its reverse (54102122112), we get a palindrome (75224242257).

The spelling of 21122120145 in words is "twenty-one billion, one hundred twenty-two million, one hundred twenty thousand, one hundred forty-five".