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20400231421 = 171200013613
BaseRepresentation
bin10010111111111100…
…101101001111111101
31221122201122010112201
4102333330231033331
5313234424401141
613212143431501
71321352051233
oct227774551775
957581563481
1020400231421
118719442899
123b53bb5591
131c0159a66b
14db750a953
157e5e78031
hex4bff2d3fd

20400231421 has 4 divisors (see below), whose sum is σ = 21600245052. Its totient is φ = 19200217792.

The previous prime is 20400231329. The next prime is 20400231437. The reversal of 20400231421 is 12413200402.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6188968900 + 14211262521 = 78670^2 + 119211^2 .

It is not a de Polignac number, because 20400231421 - 225 = 20366676989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20400231121) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 600006790 + ... + 600006823.

It is an arithmetic number, because the mean of its divisors is an integer number (5400061263).

Almost surely, 220400231421 is an apocalyptic number.

It is an amenable number.

20400231421 is a deficient number, since it is larger than the sum of its proper divisors (1200013631).

20400231421 is a wasteful number, since it uses less digits than its factorization.

20400231421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1200013630.

The product of its (nonzero) digits is 384, while the sum is 19.

Adding to 20400231421 its reverse (12413200402), we get a palindrome (32813431823).

The spelling of 20400231421 in words is "twenty billion, four hundred million, two hundred thirty-one thousand, four hundred twenty-one".

Divisors: 1 17 1200013613 20400231421