1253721 has 16 divisors (see below), whose sum is σ = 1926144. Its totient is φ = 710544.

The previous prime is 1253717. The next prime is 1253723. The reversal of 1253721 is 1273521.

1253721 = T₅₉₅ + T₅₉₆ + ... + T₆₀₁.

It is not a de Polignac number, because 1253721 - 2² = 1253717 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (1253723) 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, 4636 + ... + 4898.

It is an arithmetic number, because the mean of its divisors is an integer number (120384).

2^1253721 is an apocalyptic number.

It is an amenable number.

1253721 is a deficient number, since it is larger than the sum of its proper divisors (672423).

1253721 is a wasteful number, since it uses less digits than its factorization.

1253721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 500.

The product of its digits is 420, while the sum is 21.

The square root of 1253721 is about 1119.6968339689. The cubic root of 1253721 is about 107.8285173010.

The spelling of 1253721 in words is "one million, two hundred fifty-three thousand, seven hundred twenty-one".