261446981421 has 16 divisors (see below), whose sum is σ = 363059998848. Its totient is φ = 167198673600.

The previous prime is 261446981407. The next prime is 261446981447. The reversal of 261446981421 is 124189644162.

It is a de Polignac number, because none of the positive numbers 2^k-261446981421 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261446981491) 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, 16579290 + ... + 16595051.

It is an arithmetic number, because the mean of its divisors is an integer number (22691249928).

Almost surely, 2^261446981421 is an apocalyptic number.

It is an amenable number.

261446981421 is a deficient number, since it is larger than the sum of its proper divisors (101613017427).

261446981421 is a wasteful number, since it uses less digits than its factorization.

261446981421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33174452.

The product of its digits is 663552, while the sum is 48.

The spelling of 261446981421 in words is "two hundred sixty-one billion, four hundred forty-six million, nine hundred eighty-one thousand, four hundred twenty-one".