165143141556421 has 6 divisors (see below), whose sum is σ = 192105287116710. Its totient is φ = 141551264191176.

The previous prime is 165143141556397. The next prime is 165143141556427. The reversal of 165143141556421 is 124655141341561.

It can be written as a sum of positive squares in only one way, i.e., 114113349288225 + 51029792268196 = 10682385^2 + 7143514^2 .

It is not a de Polignac number, because 165143141556421 - 2⁵ = 165143141556389 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (49), and also a Moran number because the ratio is a prime number: 3370268195029 = 165143141556421 / (1 + 6 + 5 + 1 + 4 + 3 + 1 + 4 + 1 + 5 + 5 + 6 + 4 + 2 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165143141556427) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1685134097466 + ... + 1685134097563.

It is an arithmetic number, because the mean of its divisors is an integer number (32017547852785).

Almost surely, 2^{165143141556421} is an apocalyptic number.

It is an amenable number.

165143141556421 is a deficient number, since it is larger than the sum of its proper divisors (26962145560289).

165143141556421 is an equidigital number, since it uses as much as digits as its factorization.

165143141556421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3370268195043 (or 3370268195036 counting only the distinct ones).

The product of its digits is 1728000, while the sum is 49.

Adding to 165143141556421 its reverse (124655141341561), we get a palindrome (289798282897982).

The spelling of 165143141556421 in words is "one hundred sixty-five trillion, one hundred forty-three billion, one hundred forty-one million, five hundred fifty-six thousand, four hundred twenty-one".