1340721 has 12 divisors (see below), whose sum is σ = 1946880. Its totient is φ = 889080.

The previous prime is 1340707. The next prime is 1340723. The reversal of 1340721 is 1270431.

It is a de Polignac number, because none of the positive numbers 2^k-1340721 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1340694 and 1340703.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1340723) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2560 + ... + 3038.

It is an arithmetic number, because the mean of its divisors is an integer number (162240).

2^1340721 is an apocalyptic number.

It is an amenable number.

1340721 is a deficient number, since it is larger than the sum of its proper divisors (606159).

1340721 is a wasteful number, since it uses less digits than its factorization.

1340721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 796 (or 793 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 1340721 is about 1157.8950729665. The cubic root of 1340721 is about 110.2671468233.

Subtracting from 1340721 its sum of digits (18), we obtain a triangular number (1340703 = T₁₆₃₇).

The spelling of 1340721 in words is "one million, three hundred forty thousand, seven hundred twenty-one".