1261375490 has 16 divisors (see below), whose sum is σ = 2270893752. Its totient is φ = 504457344.

The previous prime is 1261375481. The next prime is 1261375501. The reversal of 1261375490 is 945731621.

It can be written as a sum of positive squares in 4 ways, for example, as 706443241 + 554932249 = 26579^2 + 23557^2 .

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 79502 + ... + 94038.

Almost surely, 2^1261375490 is an apocalyptic number.

1261375490 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1261375490 is a deficient number, since it is larger than the sum of its proper divisors (1009518262).

1261375490 is a wasteful number, since it uses less digits than its factorization.

1261375490 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23221.

The product of its (nonzero) digits is 45360, while the sum is 38.

The square root of 1261375490 is about 35515.8484341850. The cubic root of 1261375490 is about 1080.4751824149.

The spelling of 1261375490 in words is "one billion, two hundred sixty-one million, three hundred seventy-five thousand, four hundred ninety".