221266731 has 16 divisors (see below), whose sum is σ = 337376768. Its totient is φ = 126360000.

The previous prime is 221266673. The next prime is 221266753. The reversal of 221266731 is 137662122.

It is not a de Polignac number, because 221266731 - 2¹⁷ = 221135659 is a prime.

It is a super-2 number, since 2×221266731² = 97917932494852722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221266531) 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, 61266 + ... + 64776.

It is an arithmetic number, because the mean of its divisors is an integer number (21086048).

Almost surely, 2^221266731 is an apocalyptic number.

221266731 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

221266731 is a deficient number, since it is larger than the sum of its proper divisors (116110037).

221266731 is a wasteful number, since it uses less digits than its factorization.

221266731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6522.

The product of its digits is 6048, while the sum is 30.

The square root of 221266731 is about 14875.0371764241. The cubic root of 221266731 is about 604.8374956851.

The spelling of 221266731 in words is "two hundred twenty-one million, two hundred sixty-six thousand, seven hundred thirty-one".