2991621 has 4 divisors (see below), whose sum is σ = 3988832. Its totient is φ = 1994412.

The previous prime is 2991619. The next prime is 2991629. The reversal of 2991621 is 1261992.

It is a happy number.

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 not a de Polignac number, because 2991621 - 2¹ = 2991619 is a prime.

It is a D-number.

It is a Duffinian number.

2991621 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2991629) 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, 498601 + ... + 498606.

It is an arithmetic number, because the mean of its divisors is an integer number (997208).

2^2991621 is an apocalyptic number.

It is an amenable number.

2991621 is a deficient number, since it is larger than the sum of its proper divisors (997211).

2991621 is an equidigital number, since it uses as much as digits as its factorization.

2991621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 997210.

The product of its digits is 1944, while the sum is 30.

The square root of 2991621 is about 1729.6303073200. The cubic root of 2991621 is about 144.0905583928.

The spelling of 2991621 in words is "two million, nine hundred ninety-one thousand, six hundred twenty-one".