261434435220 has 480 divisors, whose sum is σ = 951202086912. Its totient is φ = 58876699392.

The previous prime is 261434435201. The next prime is 261434435231. The reversal of 261434435220 is 22534434162.

261434435220 is a `hidden beast` number, since 2 + 6 + 143 + 443 + 52 + 20 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 240509517 + ... + 240510603.

Almost surely, 2^261434435220 is an apocalyptic number.

261434435220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261434435220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (475601043456).

261434435220 is an abundant number, since it is smaller than the sum of its proper divisors (689767651692).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261434435220 is a wasteful number, since it uses less digits than its factorization.

261434435220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1409 (or 1398 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 36.

Adding to 261434435220 its reverse (22534434162), we get a palindrome (283968869382).

The spelling of 261434435220 in words is "two hundred sixty-one billion, four hundred thirty-four million, four hundred thirty-five thousand, two hundred twenty".