221132431 has 16 divisors (see below), whose sum is σ = 251923840. Its totient is φ = 192417120.

The previous prime is 221132423. The next prime is 221132437. The reversal of 221132431 is 134231122.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 221132431 - 2³ = 221132423 is a prime.

It is a super-2 number, since 2×221132431² = 97799104079939522, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221132399 and 221132408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221132437) 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, 49996 + ... + 54238.

It is an arithmetic number, because the mean of its divisors is an integer number (15745240).

Almost surely, 2^221132431 is an apocalyptic number.

221132431 is the 8586-th hex number.

221132431 is a deficient number, since it is larger than the sum of its proper divisors (30791409).

221132431 is a wasteful number, since it uses less digits than its factorization.

221132431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4486.

The product of its digits is 288, while the sum is 19.

The square root of 221132431 is about 14870.5222167885. The cubic root of 221132431 is about 604.7151002467.

Adding to 221132431 its reverse (134231122), we get a palindrome (355363553).

The spelling of 221132431 in words is "two hundred twenty-one million, one hundred thirty-two thousand, four hundred thirty-one".