1451125721 has 4 divisors (see below), whose sum is σ = 1451218944. Its totient is φ = 1451032500.

The previous prime is 1451125699. The next prime is 1451125733. The reversal of 1451125721 is 1275211541.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1275211541 = 1637 ⋅778993.

It is a cyclic number.

It is not a de Polignac number, because 1451125721 - 2⁶ = 1451125657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1451125771) 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, 16985 + ... + 56486.

It is an arithmetic number, because the mean of its divisors is an integer number (362804736).

Almost surely, 2^1451125721 is an apocalyptic number.

It is an amenable number.

1451125721 is a deficient number, since it is larger than the sum of its proper divisors (93223).

1451125721 is an equidigital number, since it uses as much as digits as its factorization.

1451125721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93222.

The product of its digits is 2800, while the sum is 29.

The square root of 1451125721 is about 38093.6441023959. The cubic root of 1451125721 is about 1132.1440279330.

The spelling of 1451125721 in words is "one billion, four hundred fifty-one million, one hundred twenty-five thousand, seven hundred twenty-one".