1221351670 has 64 divisors (see below), whose sum is σ = 2758634496. Its totient is φ = 378218880.

The previous prime is 1221351653. The next prime is 1221351697. The reversal of 1221351670 is 761531221.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 115839 + ... + 125941.

It is an arithmetic number, because the mean of its divisors is an integer number (43103664).

Almost surely, 2^1221351670 is an apocalyptic number.

1221351670 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1221351670 is an abundant number, since it is smaller than the sum of its proper divisors (1537282826).

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

1221351670 is a wasteful number, since it uses less digits than its factorization.

1221351670 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10285.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 1221351670 is about 34947.8421365326. The cubic root of 1221351670 is about 1068.9242018745.

Adding to 1221351670 its reverse (761531221), we get a palindrome (1982882891).

The spelling of 1221351670 in words is "one billion, two hundred twenty-one million, three hundred fifty-one thousand, six hundred seventy".