1221793651 has 16 divisors (see below), whose sum is σ = 1386276640. Its totient is φ = 1067489280.

The previous prime is 1221793633. The next prime is 1221793663. The reversal of 1221793651 is 1563971221.

It is not a de Polignac number, because 1221793651 - 2⁵ = 1221793619 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1221793651.

It is not an unprimeable number, because it can be changed into a prime (1221793151) 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, 520741 + ... + 523081.

It is an arithmetic number, because the mean of its divisors is an integer number (86642290).

Almost surely, 2^1221793651 is an apocalyptic number.

1221793651 is a deficient number, since it is larger than the sum of its proper divisors (164482989).

1221793651 is a wasteful number, since it uses less digits than its factorization.

1221793651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4486.

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

The square root of 1221793651 is about 34954.1650021854. The cubic root of 1221793651 is about 1069.0531265792.

The spelling of 1221793651 in words is "one billion, two hundred twenty-one million, seven hundred ninety-three thousand, six hundred fifty-one".