21020400313145 has 16 divisors (see below), whose sum is σ = 25646971258128. Its totient is φ = 16534852669440.

The previous prime is 21020400313141. The next prime is 21020400313243. The reversal of 21020400313145 is 54131300402012.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 1289071849129 + 19731328464016 = 1135373^2 + 4441996^2 .

It is not a de Polignac number, because 21020400313145 - 2² = 21020400313141 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21020400313141) 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, 11190104 + ... + 12932873.

It is an arithmetic number, because the mean of its divisors is an integer number (1602935703633).

Almost surely, 2^{21020400313145} is an apocalyptic number.

It is an amenable number.

21020400313145 is a deficient number, since it is larger than the sum of its proper divisors (4626570944983).

21020400313145 is a wasteful number, since it uses less digits than its factorization.

21020400313145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24125900.

The product of its (nonzero) digits is 2880, while the sum is 26.

Adding to 21020400313145 its reverse (54131300402012), we get a palindrome (75151700715157).

The spelling of 21020400313145 in words is "twenty-one trillion, twenty billion, four hundred million, three hundred thirteen thousand, one hundred forty-five".