1221193657 has 8 divisors (see below), whose sum is σ = 1312328736. Its totient is φ = 1132203072.

The previous prime is 1221193643. The next prime is 1221193663. The reversal of 1221193657 is 7563911221.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1221193657 - 2⁷ = 1221193529 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1221193637) 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, 534943 + ... + 537220.

It is an arithmetic number, because the mean of its divisors is an integer number (164041092).

Almost surely, 2^1221193657 is an apocalyptic number.

1221193657 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

1221193657 is a deficient number, since it is larger than the sum of its proper divisors (91135079).

1221193657 is a wasteful number, since it uses less digits than its factorization.

1221193657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1072247.

The product of its digits is 22680, while the sum is 37.

The square root of 1221193657 is about 34945.5813658895. The cubic root of 1221193657 is about 1068.8781023471.

The spelling of 1221193657 in words is "one billion, two hundred twenty-one million, one hundred ninety-three thousand, six hundred fifty-seven".