1221511996 has 24 divisors (see below), whose sum is σ = 2165691024. Its totient is φ = 602759040.

The previous prime is 1221511961. The next prime is 1221512009. The reversal of 1221511996 is 6991151221.

It is a hoax number, since the sum of its digits (37) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 534376 + ... + 536656.

It is an arithmetic number, because the mean of its divisors is an integer number (90237126).

Almost surely, 2^1221511996 is an apocalyptic number.

It is an amenable number.

1221511996 is a deficient number, since it is larger than the sum of its proper divisors (944179028).

1221511996 is a wasteful number, since it uses less digits than its factorization.

1221511996 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3981 (or 3979 counting only the distinct ones).

The product of its digits is 9720, while the sum is 37.

The square root of 1221511996 is about 34950.1358509520. The cubic root of 1221511996 is about 1068.9709721449.

The spelling of 1221511996 in words is "one billion, two hundred twenty-one million, five hundred eleven thousand, nine hundred ninety-six".