1221012345 has 32 divisors (see below), whose sum is σ = 2304737280. Its totient is φ = 540169920.

The previous prime is 1221012337. The next prime is 1221012361. The reversal of 1221012345 is 5432101221.

1221012345 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 1221012345 - 2³ = 1221012337 is a prime.

It is a super-2 number, since 2×1221012345² = 2981742293284798050, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 184305 + ... + 190814.

It is an arithmetic number, because the mean of its divisors is an integer number (72023040).

Almost surely, 2^1221012345 is an apocalyptic number.

1221012345 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1221012345 is a deficient number, since it is larger than the sum of its proper divisors (1083724935).

1221012345 is a wasteful number, since it uses less digits than its factorization.

1221012345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 375165.

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 1221012345 is about 34942.9870646457. The cubic root of 1221012345 is about 1068.8252005496.

Adding to 1221012345 its reverse (5432101221), we get a palindrome (6653113566).

The spelling of 1221012345 in words is "one billion, two hundred twenty-one million, twelve thousand, three hundred forty-five".