1261657672 has 64 divisors (see below), whose sum is σ = 2659392000. Its totient is φ = 556093440.

The previous prime is 1261657667. The next prime is 1261657679. The reversal of 1261657672 is 2767561621.

It is not an unprimeable number, because it can be changed into a prime (1261657679) 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, 1461513 + ... + 1462375.

It is an arithmetic number, because the mean of its divisors is an integer number (41553000).

Almost surely, 2^1261657672 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1261657672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1329696000).

1261657672 is an abundant number, since it is smaller than the sum of its proper divisors (1397734328).

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

1261657672 is a wasteful number, since it uses less digits than its factorization.

1261657672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1366 (or 1362 counting only the distinct ones).

The product of its digits is 211680, while the sum is 43.

The square root of 1261657672 is about 35519.8208328815. The cubic root of 1261657672 is about 1080.5557473530. Note that the first 3 decimals are identical.

The spelling of 1261657672 in words is "one billion, two hundred sixty-one million, six hundred fifty-seven thousand, six hundred seventy-two".