221070691 has 4 divisors (see below), whose sum is σ = 221229000. Its totient is φ = 220912384.

The previous prime is 221070659. The next prime is 221070709. The reversal of 221070691 is 196070122.

It is a happy number.

221070691 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 a cyclic number.

It is not a de Polignac number, because 221070691 - 2⁵ = 221070659 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221070391) 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, 77041 + ... + 79858.

It is an arithmetic number, because the mean of its divisors is an integer number (55307250).

Almost surely, 2^221070691 is an apocalyptic number.

221070691 is a deficient number, since it is larger than the sum of its proper divisors (158309).

221070691 is a wasteful number, since it uses less digits than its factorization.

221070691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 158308.

The product of its (nonzero) digits is 1512, while the sum is 28.

The square root of 221070691 is about 14868.4461528433. The cubic root of 221070691 is about 604.6588163489.

The spelling of 221070691 in words is "two hundred twenty-one million, seventy thousand, six hundred ninety-one".