2157784 has 8 divisors (see below), whose sum is σ = 4045860. Its totient is φ = 1078888.

The previous prime is 2157769. The next prime is 2157787. The reversal of 2157784 is 4877512.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (8).

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2157787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 134854 + ... + 134869.

2^2157784 is an apocalyptic number.

It is an amenable number.

2157784 is a deficient number, since it is larger than the sum of its proper divisors (1888076).

2157784 is a wasteful number, since it uses less digits than its factorization.

2157784 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 269729 (or 269725 counting only the distinct ones).

The product of its digits is 15680, while the sum is 34.

The square root of 2157784 is about 1468.9397536999. The cubic root of 2157784 is about 129.2218604679.

The spelling of 2157784 in words is "two million, one hundred fifty-seven thousand, seven hundred eighty-four".