1221564123 has 48 divisors (see below), whose sum is σ = 1935198720. Its totient is φ = 738009792.

The previous prime is 1221564119. The next prime is 1221564137. The reversal of 1221564123 is 3214651221.

1221564123 is a `hidden beast` number, since 1 + 2 + 2 + 15 + 641 + 2 + 3 = 666.

It is not a de Polignac number, because 1221564123 - 2² = 1221564119 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1221564163) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2615536 + ... + 2616002.

It is an arithmetic number, because the mean of its divisors is an integer number (40316640).

Almost surely, 2^1221564123 is an apocalyptic number.

1221564123 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

1221564123 is a deficient number, since it is larger than the sum of its proper divisors (713634597).

1221564123 is a wasteful number, since it uses less digits than its factorization.

1221564123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 848 (or 845 counting only the distinct ones).

The product of its digits is 2880, while the sum is 27.

The square root of 1221564123 is about 34950.8815768644. The cubic root of 1221564123 is about 1068.9861777418.

The spelling of 1221564123 in words is "one billion, two hundred twenty-one million, five hundred sixty-four thousand, one hundred twenty-three".