1221606465 has 16 divisors (see below), whose sum is σ = 1960378368. Its totient is φ = 649587456.

The previous prime is 1221606461. The next prime is 1221606473. The reversal of 1221606465 is 5646061221.

It is not a de Polignac number, because 1221606465 - 2² = 1221606461 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1221606461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 115777 + ... + 125886.

It is an arithmetic number, because the mean of its divisors is an integer number (122523648).

Almost surely, 2^1221606465 is an apocalyptic number.

1221606465 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1221606465 is a deficient number, since it is larger than the sum of its proper divisors (738771903).

1221606465 is a wasteful number, since it uses less digits than its factorization.

1221606465 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 242008.

The product of its (nonzero) digits is 17280, while the sum is 33.

The square root of 1221606465 is about 34951.4873074094. The cubic root of 1221606465 is about 1068.9985287075.

Adding to 1221606465 its reverse (5646061221), we get a palindrome (6867667686).

The spelling of 1221606465 in words is "one billion, two hundred twenty-one million, six hundred six thousand, four hundred sixty-five".