221291649 has 16 divisors (see below), whose sum is σ = 329125440. Its totient is φ = 146949120.

The previous prime is 221291639. The next prime is 221291683. The reversal of 221291649 is 946192122.

221291649 is a `hidden beast` number, since 2 + 2 + 1 + 2 + 9 + 1 + 649 = 666.

It is not a de Polignac number, because 221291649 - 2⁴ = 221291633 is a prime.

It is not an unprimeable number, because it can be changed into a prime (221291639) 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, 9007 + ... + 22884.

It is an arithmetic number, because the mean of its divisors is an integer number (20570340).

Almost surely, 2^221291649 is an apocalyptic number.

It is an amenable number.

221291649 is a deficient number, since it is larger than the sum of its proper divisors (107833791).

221291649 is a wasteful number, since it uses less digits than its factorization.

221291649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32157 (or 32151 counting only the distinct ones).

The product of its digits is 15552, while the sum is 36.

The square root of 221291649 is about 14875.8747305831. The cubic root of 221291649 is about 604.8601994673.

The spelling of 221291649 in words is "two hundred twenty-one million, two hundred ninety-one thousand, six hundred forty-nine".