1221400373 has 8 divisors (see below), whose sum is σ = 1263582936. Its totient is φ = 1179808000.

The previous prime is 1221400339. The next prime is 1221400409. The reversal of 1221400373 is 3730041221.

It can be written as a sum of positive squares in 4 ways, for example, as 46144849 + 1175255524 = 6793^2 + 34282^2 .

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 1221400373 - 2¹⁶ = 1221334837 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221400333) 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, 143336 + ... + 151617.

It is an arithmetic number, because the mean of its divisors is an integer number (157947867).

Almost surely, 2^1221400373 is an apocalyptic number.

It is an amenable number.

1221400373 is a deficient number, since it is larger than the sum of its proper divisors (42182563).

1221400373 is a wasteful number, since it uses less digits than its factorization.

1221400373 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 295095.

The product of its (nonzero) digits is 1008, while the sum is 23.

The square root of 1221400373 is about 34948.5389251110. The cubic root of 1221400373 is about 1068.9384099373.

Adding to 1221400373 its reverse (3730041221), we get a palindrome (4951441594).

The spelling of 1221400373 in words is "one billion, two hundred twenty-one million, four hundred thousand, three hundred seventy-three".