1261415550 has 24 divisors (see below), whose sum is σ = 3128310936. Its totient is φ = 336377440.

The previous prime is 1261415549. The next prime is 1261415557. The reversal of 1261415550 is 555141621.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1261415557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4204569 + ... + 4204868.

It is an arithmetic number, because the mean of its divisors is an integer number (130346289).

Almost surely, 2^1261415550 is an apocalyptic number.

1261415550 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1261415550 is an abundant number, since it is smaller than the sum of its proper divisors (1866895386).

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

1261415550 is a wasteful number, since it uses less digits than its factorization.

1261415550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8409452 (or 8409447 counting only the distinct ones).

The product of its (nonzero) digits is 6000, while the sum is 30.

The square root of 1261415550 is about 35516.4124032820. The cubic root of 1261415550 is about 1080.4866205573.

The spelling of 1261415550 in words is "one billion, two hundred sixty-one million, four hundred fifteen thousand, five hundred fifty".