1261767690 has 24 divisors (see below), whose sum is σ = 3280596228. Its totient is φ = 336471360.

The previous prime is 1261767623. The next prime is 1261767691. The reversal of 1261767690 is 967671621.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 1169434809 + 92332881 = 34197^2 + 9609^2 .

It is a super-2 number, since 2×1261767690² = 3184115407055872200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (1261767691) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7009731 + ... + 7009910.

Almost surely, 2^1261767690 is an apocalyptic number.

1261767690 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1261767690 is an abundant number, since it is smaller than the sum of its proper divisors (2018828538).

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

1261767690 is a wasteful number, since it uses less digits than its factorization.

1261767690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14019654 (or 14019651 counting only the distinct ones).

The product of its (nonzero) digits is 190512, while the sum is 45.

The square root of 1261767690 is about 35521.3694837347. The cubic root of 1261767690 is about 1080.5871550081.

The spelling of 1261767690 in words is "one billion, two hundred sixty-one million, seven hundred sixty-seven thousand, six hundred ninety".