4021957 has 4 divisors (see below), whose sum is σ = 4049100. Its totient is φ = 3994816.

The previous prime is 4021949. The next prime is 4021961. The reversal of 4021957 is 7591204.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 312481 + 3709476 = 559^2 + 1926^2 .

It is a cyclic number.

It is not a de Polignac number, because 4021957 - 2³ = 4021949 is a prime.

It is a super-2 number, since 2×4021957² = 32352276219698, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is a nialpdrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4021907) 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, 13348 + ... + 13645.

It is an arithmetic number, because the mean of its divisors is an integer number (1012275).

Almost surely, 2^4021957 is an apocalyptic number.

It is an amenable number.

4021957 is a deficient number, since it is larger than the sum of its proper divisors (27143).

4021957 is a wasteful number, since it uses less digits than its factorization.

4021957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27142.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 4021957 is about 2005.4817376381. The cubic root of 4021957 is about 159.0300300596.

The spelling of 4021957 in words is "four million, twenty-one thousand, nine hundred fifty-seven".