2155901 has 4 divisors (see below), whose sum is σ = 2351904. Its totient is φ = 1959900.

The previous prime is 2155883. The next prime is 2155931. The reversal of 2155901 is 1095512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2155901 - 2⁶ = 2155837 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 (2155931) 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, 97985 + ... + 98006.

It is an arithmetic number, because the mean of its divisors is an integer number (587976).

2^2155901 is an apocalyptic number.

It is an amenable number.

2155901 is a deficient number, since it is larger than the sum of its proper divisors (196003).

2155901 is a wasteful number, since it uses less digits than its factorization.

2155901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 196002.

The product of its (nonzero) digits is 450, while the sum is 23.

The square root of 2155901 is about 1468.2986753382. The cubic root of 2155901 is about 129.1842608476.

It can be divided in two parts, 215 and 5901, that added together give a palindrome (6116).

The spelling of 2155901 in words is "two million, one hundred fifty-five thousand, nine hundred one".