2621391 has 16 divisors (see below), whose sum is σ = 3667968. Its totient is φ = 1663200.

The previous prime is 2621387. The next prime is 2621431. The reversal of 2621391 is 1931262.

Added to its reverse (1931262) it gives a triangular number (4552653 = T₃₀₁₇).

It is not a de Polignac number, because 2621391 - 2² = 2621387 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2621351) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6405 + ... + 6801.

It is an arithmetic number, because the mean of its divisors is an integer number (229248).

2^2621391 is an apocalyptic number.

2621391 is a deficient number, since it is larger than the sum of its proper divisors (1046577).

2621391 is a wasteful number, since it uses less digits than its factorization.

2621391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 502.

The product of its digits is 648, while the sum is 24.

The square root of 2621391 is about 1619.0710299428. The cubic root of 2621391 is about 137.8829610478.

Adding to 2621391 its reverse (1931262), we get a triangular number (4552653 = T₃₀₁₇).

It can be divided in two parts, 262 and 1391, that added together give a triangular number (1653 = T₅₇).

The spelling of 2621391 in words is "two million, six hundred twenty-one thousand, three hundred ninety-one".