1221946405 has 8 divisors (see below), whose sum is σ = 1479312792. Its totient is φ = 968905728.

The previous prime is 1221946399. The next prime is 1221946409. The reversal of 1221946405 is 5046491221.

It can be written as a sum of positive squares in 4 ways, for example, as 933156 + 1221013249 = 966^2 + 34943^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1221946405 - 2¹³ = 1221938213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221946409) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1080804 + ... + 1081933.

It is an arithmetic number, because the mean of its divisors is an integer number (184914099).

Almost surely, 2^1221946405 is an apocalyptic number.

It is an amenable number.

1221946405 is a deficient number, since it is larger than the sum of its proper divisors (257366387).

1221946405 is a wasteful number, since it uses less digits than its factorization.

1221946405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2162855.

The product of its (nonzero) digits is 17280, while the sum is 34.

The square root of 1221946405 is about 34956.3499953871. The cubic root of 1221946405 is about 1069.0976772926.

The spelling of 1221946405 in words is "one billion, two hundred twenty-one million, nine hundred forty-six thousand, four hundred five".