221423531 has 16 divisors (see below), whose sum is σ = 256002048. Its totient is φ = 187596000.

The previous prime is 221423479. The next prime is 221423539. The reversal of 221423531 is 135324122.

It is a cyclic number.

It is not a de Polignac number, because 221423531 - 2⁶ = 221423467 is a prime.

It is a super-2 number, since 2×221423531² = 98056760161015922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221423497 and 221423506.

It is not an unprimeable number, because it can be changed into a prime (221423539) 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, 286061 + ... + 286833.

It is an arithmetic number, because the mean of its divisors is an integer number (16000128).

Almost surely, 2^221423531 is an apocalyptic number.

221423531 is a deficient number, since it is larger than the sum of its proper divisors (34578517).

221423531 is a wasteful number, since it uses less digits than its factorization.

221423531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1202.

The product of its digits is 1440, while the sum is 23.

The square root of 221423531 is about 14880.3068180733. The cubic root of 221423531 is about 604.9803340373.

Adding to 221423531 its reverse (135324122), we get a palindrome (356747653).

The spelling of 221423531 in words is "two hundred twenty-one million, four hundred twenty-three thousand, five hundred thirty-one".