261621144164 has 6 divisors (see below), whose sum is σ = 457837002294. Its totient is φ = 130810572080.

The previous prime is 261621144163. The next prime is 261621144217. The reversal of 261621144164 is 461441126162.

It can be written as a sum of positive squares in only one way, i.e., 142763065600 + 118858078564 = 377840^2 + 344758^2 .

It is not an unprimeable number, because it can be changed into a prime (261621144163) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32702643017 + ... + 32702643024.

It is an arithmetic number, because the mean of its divisors is an integer number (76306167049).

Almost surely, 2^261621144164 is an apocalyptic number.

It is an amenable number.

261621144164 is a deficient number, since it is larger than the sum of its proper divisors (196215858130).

261621144164 is a wasteful number, since it uses less digits than its factorization.

261621144164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65405286045 (or 65405286043 counting only the distinct ones).

The product of its digits is 55296, while the sum is 38.

The spelling of 261621144164 in words is "two hundred sixty-one billion, six hundred twenty-one million, one hundred forty-four thousand, one hundred sixty-four".