221312763 has 36 divisors (see below), whose sum is σ = 382335480. Its totient is φ = 126155232.

The previous prime is 221312759. The next prime is 221312771. The reversal of 221312763 is 367213122.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It is not a de Polignac number, because 221312763 - 2² = 221312759 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (221312743) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 540903 + ... + 541311.

It is an arithmetic number, because the mean of its divisors is an integer number (10620430).

Almost surely, 2^221312763 is an apocalyptic number.

221312763 is a deficient number, since it is larger than the sum of its proper divisors (161022717).

221312763 is an frugal number, since it uses more digits than its factorization.

221312763 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 841 (or 419 counting only the distinct ones).

The product of its digits is 3024, while the sum is 27.

The square root of 221312763 is about 14876.5843862091. The cubic root of 221312763 is about 604.8794359397.

Multiplying 221312763 by its sum of digits (27), we get a square (5975444601 = 77301²).

221312763 divided by its sum of digits (27) gives a square (8196769 = 2863²).

Adding to 221312763 its reverse (367213122), we get a palindrome (588525885).

The spelling of 221312763 in words is "two hundred twenty-one million, three hundred twelve thousand, seven hundred sixty-three".