1340497021 has 4 divisors (see below), whose sum is σ = 1362472444. Its totient is φ = 1318521600.

The previous prime is 1340497001. The next prime is 1340497033. The reversal of 1340497021 is 1207940431.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1207940431 = 103 ⋅11727577.

It can be written as a sum of positive squares in 2 ways, for example, as 635594521 + 704902500 = 25211^2 + 26550^2 .

It is a cyclic number.

It is not a de Polignac number, because 1340497021 - 2¹⁵ = 1340464253 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1340497001) 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, 10987620 + ... + 10987741.

It is an arithmetic number, because the mean of its divisors is an integer number (340618111).

Almost surely, 2^1340497021 is an apocalyptic number.

It is an amenable number.

1340497021 is a deficient number, since it is larger than the sum of its proper divisors (21975423).

1340497021 is an equidigital number, since it uses as much as digits as its factorization.

1340497021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21975422.

The product of its (nonzero) digits is 6048, while the sum is 31.

The square root of 1340497021 is about 36612.7985955731. The cubic root of 1340497021 is about 1102.6100612216.

The spelling of 1340497021 in words is "one billion, three hundred forty million, four hundred ninety-seven thousand, twenty-one".