221138493 has 8 divisors (see below), whose sum is σ = 295468800. Its totient is φ = 147116928.

The previous prime is 221138483. The next prime is 221138497. The reversal of 221138493 is 394831122.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 221138493 - 2⁶ = 221138429 is a prime.

It is a super-2 number, since 2×221138493² = 97804466172622098, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221138497) 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, 75508 + ... + 78381.

It is an arithmetic number, because the mean of its divisors is an integer number (36933600).

Almost surely, 2^221138493 is an apocalyptic number.

It is an amenable number.

221138493 is a deficient number, since it is larger than the sum of its proper divisors (74330307).

221138493 is a wasteful number, since it uses less digits than its factorization.

221138493 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154371.

The product of its digits is 10368, while the sum is 33.

The square root of 221138493 is about 14870.7260414547. The cubic root of 221138493 is about 604.7206259694.

It can be divided in two parts, 2211 and 38493, that added together give a palindrome (40704).

The spelling of 221138493 in words is "two hundred twenty-one million, one hundred thirty-eight thousand, four hundred ninety-three".