253197721 has 8 divisors (see below), whose sum is σ = 289543104. Its totient is φ = 216895920.

The previous prime is 253197719. The next prime is 253197751. The reversal of 253197721 is 127791352.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 253197721 - 2¹ = 253197719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (253197701) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2691 + ... + 22663.

It is an arithmetic number, because the mean of its divisors is an integer number (36192888).

Almost surely, 2^253197721 is an apocalyptic number.

It is an amenable number.

253197721 is a deficient number, since it is larger than the sum of its proper divisors (36345383).

253197721 is a wasteful number, since it uses less digits than its factorization.

253197721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21791.

The product of its digits is 26460, while the sum is 37.

The square root of 253197721 is about 15912.1878131199. The cubic root of 253197721 is about 632.6350712174.

The spelling of 253197721 in words is "two hundred fifty-three million, one hundred ninety-seven thousand, seven hundred twenty-one".