253643721 has 8 divisors (see below), whose sum is σ = 338514624. Its totient is φ = 168934320.

The previous prime is 253643693. The next prime is 253643759. The reversal of 253643721 is 127346352.

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

It is not a de Polignac number, because 253643721 - 2¹¹ = 253641673 is a prime.

It is not an unprimeable number, because it can be changed into a prime (253643321) 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, 36661 + ... + 43026.

It is an arithmetic number, because the mean of its divisors is an integer number (42314328).

Almost surely, 2^253643721 is an apocalyptic number.

It is an amenable number.

253643721 is a deficient number, since it is larger than the sum of its proper divisors (84870903).

253643721 is a wasteful number, since it uses less digits than its factorization.

253643721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80751.

The product of its digits is 30240, while the sum is 33.

The square root of 253643721 is about 15926.1960618347. The cubic root of 253643721 is about 633.0063090696.

The spelling of 253643721 in words is "two hundred fifty-three million, six hundred forty-three thousand, seven hundred twenty-one".