2139921 has 12 divisors (see below), whose sum is σ = 3532672. Its totient is φ = 1222776.

The previous prime is 2139919. The next prime is 2139923. The reversal of 2139921 is 1299312.

It is an interprime number because it is at equal distance from previous prime (2139919) and next prime (2139923).

It is not a de Polignac number, because 2139921 - 2¹ = 2139919 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2139923) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 16921 + ... + 17046.

2^2139921 is an apocalyptic number.

2139921 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2139921 is a deficient number, since it is larger than the sum of its proper divisors (1392751).

2139921 is a wasteful number, since it uses less digits than its factorization.

2139921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33980 (or 33977 counting only the distinct ones).

The product of its digits is 972, while the sum is 27.

The square root of 2139921 is about 1462.8468819395. The cubic root of 2139921 is about 128.8642885020.

The spelling of 2139921 in words is "two million, one hundred thirty-nine thousand, nine hundred twenty-one".