1221902918 has 4 divisors (see below), whose sum is σ = 1832854380. Its totient is φ = 610951458.

The previous prime is 1221902917. The next prime is 1221902923. The reversal of 1221902918 is 8192091221.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8192091221 = 2203 ⋅3718607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221902917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 305475728 + ... + 305475731.

It is an arithmetic number, because the mean of its divisors is an integer number (458213595).

Almost surely, 2^1221902918 is an apocalyptic number.

1221902918 is a deficient number, since it is larger than the sum of its proper divisors (610951462).

1221902918 is an equidigital number, since it uses as much as digits as its factorization.

1221902918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 610951461.

The product of its (nonzero) digits is 5184, while the sum is 35.

The square root of 1221902918 is about 34955.7279712496. The cubic root of 1221902918 is about 1069.0849946844.

The spelling of 1221902918 in words is "one billion, two hundred twenty-one million, nine hundred two thousand, nine hundred eighteen".