221620497 has 8 divisors (see below), whose sum is σ = 337707456. Its totient is φ = 126640272.

The previous prime is 221620493. The next prime is 221620499. The reversal of 221620497 is 794026122.

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

It is not a de Polignac number, because 221620497 - 2² = 221620493 is a prime.

It is not an unprimeable number, because it can be changed into a prime (221620493) 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 7 ways as a sum of consecutive naturals, for example, 5276658 + ... + 5276699.

It is an arithmetic number, because the mean of its divisors is an integer number (42213432).

Almost surely, 2^221620497 is an apocalyptic number.

It is an amenable number.

221620497 is a deficient number, since it is larger than the sum of its proper divisors (116086959).

221620497 is a wasteful number, since it uses less digits than its factorization.

221620497 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10553367.

The product of its (nonzero) digits is 12096, while the sum is 33.

The square root of 221620497 is about 14886.9236916161. The cubic root of 221620497 is about 605.1596664394.

Subtracting 221620497 from its reverse (794026122), we obtain a square (572405625 = 23925²).

The spelling of 221620497 in words is "two hundred twenty-one million, six hundred twenty thousand, four hundred ninety-seven".