221501457 has 12 divisors (see below), whose sum is σ = 320148660. Its totient is φ = 147574368.

The previous prime is 221501453. The next prime is 221501461. The reversal of 221501457 is 754105122.

It is an interprime number because it is at equal distance from previous prime (221501453) and next prime (221501461).

It can be written as a sum of positive squares in 2 ways, for example, as 107246736 + 114254721 = 10356^2 + 10689^2 .

It is not a de Polignac number, because 221501457 - 2² = 221501453 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 221501457.

It is not an unprimeable number, because it can be changed into a prime (221501453) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9223 + ... + 22979.

It is an arithmetic number, because the mean of its divisors is an integer number (26679055).

Almost surely, 2^221501457 is an apocalyptic number.

It is an amenable number.

221501457 is a deficient number, since it is larger than the sum of its proper divisors (98647203).

221501457 is a wasteful number, since it uses less digits than its factorization.

221501457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15552 (or 15549 counting only the distinct ones).

The product of its (nonzero) digits is 2800, while the sum is 27.

The square root of 221501457 is about 14882.9250149290. The cubic root of 221501457 is about 605.0512963359.

Adding to 221501457 its reverse (754105122), we get a palindrome (975606579).

The spelling of 221501457 in words is "two hundred twenty-one million, five hundred one thousand, four hundred fifty-seven".