1221821079 has 8 divisors (see below), whose sum is σ = 1637624832. Its totient is φ = 810282360.

The previous prime is 1221821057. The next prime is 1221821089. The reversal of 1221821079 is 9701281221.

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

It is not a de Polignac number, because 1221821079 - 2¹⁵ = 1221788311 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221821089) 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, 1065589 + ... + 1066734.

It is an arithmetic number, because the mean of its divisors is an integer number (204703104).

Almost surely, 2^1221821079 is an apocalyptic number.

1221821079 is a deficient number, since it is larger than the sum of its proper divisors (415803753).

1221821079 is a wasteful number, since it uses less digits than its factorization.

1221821079 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2132517.

The product of its (nonzero) digits is 4032, while the sum is 33.

The square root of 1221821079 is about 34954.5573423552. The cubic root of 1221821079 is about 1069.0611262306.

The spelling of 1221821079 in words is "one billion, two hundred twenty-one million, eight hundred twenty-one thousand, seventy-nine".