1221657760 has 48 divisors (see below), whose sum is σ = 2895564672. Its totient is φ = 487072000.

The previous prime is 1221657743. The next prime is 1221657761. The reversal of 1221657760 is 677561221.

It is a Smith number, since the sum of its digits (37) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (1221657761) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 37485 + ... + 62035.

It is an arithmetic number, because the mean of its divisors is an integer number (60324264).

Almost surely, 2^1221657760 is an apocalyptic number.

1221657760 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221657760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1447782336).

1221657760 is an abundant number, since it is smaller than the sum of its proper divisors (1673906912).

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

1221657760 is a wasteful number, since it uses less digits than its factorization.

1221657760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24877 (or 24869 counting only the distinct ones).

The product of its (nonzero) digits is 35280, while the sum is 37.

The square root of 1221657760 is about 34952.2211025279. The cubic root of 1221657760 is about 1069.0134908397.

The spelling of 1221657760 in words is "one billion, two hundred twenty-one million, six hundred fifty-seven thousand, seven hundred sixty".