1221065402 has 4 divisors (see below), whose sum is σ = 1831598106. Its totient is φ = 610532700.

The previous prime is 1221065389. The next prime is 1221065429. The reversal of 1221065402 is 2045601221.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 2045601221 = 4657 ⋅439253.

It can be written as a sum of positive squares in only one way, i.e., 1066087801 + 154977601 = 32651^2 + 12449^2 .

It is a super-2 number, since 2×1221065402² = 2982001431922843208, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 305266349 + ... + 305266352.

Almost surely, 2^1221065402 is an apocalyptic number.

1221065402 is a deficient number, since it is larger than the sum of its proper divisors (610532704).

1221065402 is an equidigital number, since it uses as much as digits as its factorization.

1221065402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 610532703.

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 1221065402 is about 34943.7462502234. The cubic root of 1221065402 is about 1068.8406816482.

Adding to 1221065402 its reverse (2045601221), we get a palindrome (3266666623).

The spelling of 1221065402 in words is "one billion, two hundred twenty-one million, sixty-five thousand, four hundred two".