1221321010 has 32 divisors (see below), whose sum is σ = 2705697792. Its totient is φ = 386527680.

The previous prime is 1221321001. The next prime is 1221321011. The reversal of 1221321010 is 101231221.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is not an unprimeable number, because it can be changed into a prime (1221321011) 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, 670146 + ... + 671965.

It is an arithmetic number, because the mean of its divisors is an integer number (84553056).

Almost surely, 2^1221321010 is an apocalyptic number.

1221321010 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1221321010 is an abundant number, since it is smaller than the sum of its proper divisors (1484376782).

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

1221321010 is a wasteful number, since it uses less digits than its factorization.

1221321010 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1342138.

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 1221321010 is about 34947.4034800870. The cubic root of 1221321010 is about 1068.9152572790.

Adding to 1221321010 its reverse (101231221), we get a palindrome (1322552231).

The spelling of 1221321010 in words is "one billion, two hundred twenty-one million, three hundred twenty-one thousand, ten".