6738421 has 4 divisors (see below), whose sum is σ = 6744844. Its totient is φ = 6732000.

The previous prime is 6738419. The next prime is 6738427. The reversal of 6738421 is 1248376.

6738421 = T₂₁₁₈ + T₂₁₁₉ + T₂₁₂₀.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 2515396 + 4223025 = 1586^2 + 2055^2 .

It is a cyclic number.

It is not a de Polignac number, because 6738421 - 2¹ = 6738419 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 (6738427) 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, 1230 + ... + 3871.

It is an arithmetic number, because the mean of its divisors is an integer number (1686211).

Almost surely, 2^6738421 is an apocalyptic number.

6738421 is the 2120-th centered triangular number.

It is an amenable number.

6738421 is a deficient number, since it is larger than the sum of its proper divisors (6423).

6738421 is a wasteful number, since it uses less digits than its factorization.

6738421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6422.

The product of its digits is 8064, while the sum is 31.

The square root of 6738421 is about 2595.8468752991. The cubic root of 6738421 is about 188.8800317390.

The spelling of 6738421 in words is "six million, seven hundred thirty-eight thousand, four hundred twenty-one".