221634431 has 4 divisors (see below), whose sum is σ = 223379712. Its totient is φ = 219889152.

The previous prime is 221634419. The next prime is 221634451. The reversal of 221634431 is 134436122.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 134436122 = 2 ⋅67218061.

It is a cyclic number.

It is not a de Polignac number, because 221634431 - 2⁶ = 221634367 is a prime.

It is a super-2 number, since 2×221634431² = 98243642009387522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 221634431.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221634451) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 872450 + ... + 872703.

It is an arithmetic number, because the mean of its divisors is an integer number (55844928).

Almost surely, 2^221634431 is an apocalyptic number.

221634431 is a deficient number, since it is larger than the sum of its proper divisors (1745281).

221634431 is a wasteful number, since it uses less digits than its factorization.

221634431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1745280.

The product of its digits is 3456, while the sum is 26.

The square root of 221634431 is about 14887.3916788671. The cubic root of 221634431 is about 605.1723489578.

The spelling of 221634431 in words is "two hundred twenty-one million, six hundred thirty-four thousand, four hundred thirty-one".