221513951 has 4 divisors (see below), whose sum is σ = 233172600. Its totient is φ = 209855304.

The previous prime is 221513947. The next prime is 221513959. The reversal of 221513951 is 159315122.

221513951 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 221513951 - 2² = 221513947 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221513959) 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, 5829296 + ... + 5829333.

It is an arithmetic number, because the mean of its divisors is an integer number (58293150).

Almost surely, 2^221513951 is an apocalyptic number.

221513951 is a deficient number, since it is larger than the sum of its proper divisors (11658649).

221513951 is a wasteful number, since it uses less digits than its factorization.

221513951 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11658648.

The product of its digits is 2700, while the sum is 29.

The square root of 221513951 is about 14883.3447517687. The cubic root of 221513951 is about 605.0626722863.

The spelling of 221513951 in words is "two hundred twenty-one million, five hundred thirteen thousand, nine hundred fifty-one".