261636403250 has 16 divisors (see below), whose sum is σ = 489783347352. Its totient is φ = 104654561200.

The previous prime is 261636403229. The next prime is 261636403261. The reversal of 261636403250 is 52304636162.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 90082218769 + 171554184481 = 300137^2 + 414191^2 .

It is a super-2 number, since 2×261636403250² (a number of 24 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 523272557 + ... + 523273056.

Almost surely, 2^261636403250 is an apocalyptic number.

261636403250 is a deficient number, since it is larger than the sum of its proper divisors (228146944102).

261636403250 is a wasteful number, since it uses less digits than its factorization.

261636403250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1046545630 (or 1046545620 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 38.

The spelling of 261636403250 in words is "two hundred sixty-one billion, six hundred thirty-six million, four hundred three thousand, two hundred fifty".