261403621512 has 64 divisors (see below), whose sum is σ = 720268718400. Its totient is φ = 78396579840.

The previous prime is 261403621499. The next prime is 261403621513. The reversal of 261403621512 is 215126304162.

It is a super-2 number, since 2×261403621512² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (261403621513) 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, 5078337 + ... + 5129552.

It is an arithmetic number, because the mean of its divisors is an integer number (11254198725).

Almost surely, 2^261403621512 is an apocalyptic number.

261403621512 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

261403621512 is an abundant number, since it is smaller than the sum of its proper divisors (458865096888).

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

261403621512 is a wasteful number, since it uses less digits than its factorization.

261403621512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10208006 (or 10208002 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 33.

Adding to 261403621512 its reverse (215126304162), we get a palindrome (476529925674).

The spelling of 261403621512 in words is "two hundred sixty-one billion, four hundred three million, six hundred twenty-one thousand, five hundred twelve".