1221523431 has 16 divisors (see below), whose sum is σ = 1654358400. Its totient is φ = 801538848.

The previous prime is 1221523397. The next prime is 1221523451. The reversal of 1221523431 is 1343251221.

It is not a de Polignac number, because 1221523431 - 2⁹ = 1221522919 is a prime.

It is a super-2 number, since 2×1221523431² = 2984238984964023522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221523451) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 436585 + ... + 439373.

It is an arithmetic number, because the mean of its divisors is an integer number (103397400).

Almost surely, 2^1221523431 is an apocalyptic number.

1221523431 is a deficient number, since it is larger than the sum of its proper divisors (432834969).

1221523431 is a wasteful number, since it uses less digits than its factorization.

1221523431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5038.

The product of its digits is 1440, while the sum is 24.

The square root of 1221523431 is about 34950.2994407773. The cubic root of 1221523431 is about 1068.9743078046.

Adding to 1221523431 its reverse (1343251221), we get a palindrome (2564774652).

The spelling of 1221523431 in words is "one billion, two hundred twenty-one million, five hundred twenty-three thousand, four hundred thirty-one".