1221296879 has 16 divisors (see below), whose sum is σ = 1365112320. Its totient is φ = 1083015360.

The previous prime is 1221296771. The next prime is 1221296911. The reversal of 1221296879 is 9786921221.

It is a cyclic number.

It is not a de Polignac number, because 1221296879 - 2⁸ = 1221296623 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221296579) 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, 532874 + ... + 535160.

It is an arithmetic number, because the mean of its divisors is an integer number (85319520).

Almost surely, 2^1221296879 is an apocalyptic number.

1221296879 is a deficient number, since it is larger than the sum of its proper divisors (143815441).

1221296879 is a wasteful number, since it uses less digits than its factorization.

1221296879 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3470.

The product of its digits is 217728, while the sum is 47.

The square root of 1221296879 is about 34947.0582309871. The cubic root of 1221296879 is about 1068.9082173160.

The spelling of 1221296879 in words is "one billion, two hundred twenty-one million, two hundred ninety-six thousand, eight hundred seventy-nine".