1261767820 has 24 divisors (see below), whose sum is σ = 2699709264. Its totient is φ = 495183936.

The previous prime is 1261767809. The next prime is 1261767823. The reversal of 1261767820 is 287671621.

It is a hoax number, since the sum of its digits (40) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (1261767823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 594114 + ... + 596233.

It is an arithmetic number, because the mean of its divisors is an integer number (112487886).

Almost surely, 2^1261767820 is an apocalyptic number.

1261767820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1261767820 is an abundant number, since it is smaller than the sum of its proper divisors (1437941444).

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

1261767820 is a wasteful number, since it uses less digits than its factorization.

1261767820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1190409 (or 1190407 counting only the distinct ones).

The product of its (nonzero) digits is 56448, while the sum is 40.

The square root of 1261767820 is about 35521.3713136191. The cubic root of 1261767820 is about 1080.5871921191.

The spelling of 1261767820 in words is "one billion, two hundred sixty-one million, seven hundred sixty-seven thousand, eight hundred twenty".