2656421 has 4 divisors (see below), whose sum is σ = 2742144. Its totient is φ = 2570700.

The previous prime is 2656417. The next prime is 2656427. The reversal of 2656421 is 1246562.

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 an emirpimes, since its reverse is a distinct semiprime: 1246562 = 2 ⋅623281.

It is a cyclic number.

It is not a de Polignac number, because 2656421 - 2² = 2656417 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 (2656427) 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, 42815 + ... + 42876.

It is an arithmetic number, because the mean of its divisors is an integer number (685536).

2^2656421 is an apocalyptic number.

It is an amenable number.

2656421 is a deficient number, since it is larger than the sum of its proper divisors (85723).

2656421 is an equidigital number, since it uses as much as digits as its factorization.

2656421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85722.

The product of its digits is 2880, while the sum is 26.

The square root of 2656421 is about 1629.8530608616. The cubic root of 2656421 is about 138.4944282188.

The spelling of 2656421 in words is "two million, six hundred fifty-six thousand, four hundred twenty-one".