1221545431 has 8 divisors (see below), whose sum is σ = 1274951664. Its totient is φ = 1169263680.

The previous prime is 1221545383. The next prime is 1221545441. The reversal of 1221545431 is 1345451221.

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 1221545431 - 2²³ = 1213156823 is a prime.

It is a super-2 number, since 2×1221545431² = 2984346479993951522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1221545431.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221545441) 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, 278901 + ... + 283246.

It is an arithmetic number, because the mean of its divisors is an integer number (159368958).

Almost surely, 2^1221545431 is an apocalyptic number.

1221545431 is a deficient number, since it is larger than the sum of its proper divisors (53406233).

1221545431 is an equidigital number, since it uses as much as digits as its factorization.

1221545431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 562241.

The product of its digits is 4800, while the sum is 28.

The square root of 1221545431 is about 34950.6141719999. The cubic root of 1221545431 is about 1068.9807252810.

Adding to 1221545431 its reverse (1345451221), we get a palindrome (2566996652).

The spelling of 1221545431 in words is "one billion, two hundred twenty-one million, five hundred forty-five thousand, four hundred thirty-one".