1261656500 has 48 divisors (see below), whose sum is σ = 2967431376. Its totient is φ = 465840000.

The previous prime is 1261656497. The next prime is 1261656503. The reversal of 1261656500 is 56561621.

It is an interprime number because it is at equal distance from previous prime (1261656497) and next prime (1261656503).

It can be written as a sum of positive squares in 8 ways, for example, as 980691856 + 280964644 = 31316^2 + 16762^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1261656503) 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, 90551 + ... + 103550.

It is an arithmetic number, because the mean of its divisors is an integer number (61821487).

Almost surely, 2^1261656500 is an apocalyptic number.

1261656500 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1261656500 is an abundant number, since it is smaller than the sum of its proper divisors (1705774876).

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

1261656500 is a wasteful number, since it uses less digits than its factorization.

1261656500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 194133 (or 194121 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 32.

The square root of 1261656500 is about 35519.8043350467. The cubic root of 1261656500 is about 1080.5554127637. Note that the first 3 decimals are identical.

The spelling of 1261656500 in words is "one billion, two hundred sixty-one million, six hundred fifty-six thousand, five hundred".