3728421 has 6 divisors (see below), whose sum is σ = 5385510. Its totient is φ = 2485608.

The previous prime is 3728411. The next prime is 3728429. The reversal of 3728421 is 1248273.

It can be written as a sum of positive squares in only one way, i.e., 3663396 + 65025 = 1914^2 + 255^2 .

It is not a de Polignac number, because 3728421 - 2⁶ = 3728357 is a prime.

It is a super-2 number, since 2×3728421² = 27802246306482, which contains 22 as substring.

It is a d-powerful number, because it can be written as 3¹³ + 7² + 2⁵ + 8⁵ + 4⁶ + 2²¹ + 1 .

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3728429) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 207126 + ... + 207143.

It is an arithmetic number, because the mean of its divisors is an integer number (897585).

Almost surely, 2^3728421 is an apocalyptic number.

It is an amenable number.

3728421 is a deficient number, since it is larger than the sum of its proper divisors (1657089).

3728421 is a wasteful number, since it uses less digits than its factorization.

3728421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 414275 (or 414272 counting only the distinct ones).

The product of its digits is 2688, while the sum is 27.

The square root of 3728421 is about 1930.9119607067. The cubic root of 3728421 is about 155.0630475391.

The spelling of 3728421 in words is "three million, seven hundred twenty-eight thousand, four hundred twenty-one".