3551621 has 2 divisors, whose sum is σ = 3551622. Its totient is φ = 3551620.

The previous prime is 3551599. The next prime is 3551627. The reversal of 3551621 is 1261553.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2927521 + 624100 = 1711^2 + 790^2 .

It is a cyclic number.

It is not a de Polignac number, because 3551621 - 2¹⁴ = 3535237 is a prime.

It is a super-2 number, since 2×3551621² = 25228023455282, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3551627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1775810 + 1775811.

It is an arithmetic number, because the mean of its divisors is an integer number (1775811).

Almost surely, 2^3551621 is an apocalyptic number.

It is an amenable number.

3551621 is a deficient number, since it is larger than the sum of its proper divisors (1).

3551621 is an equidigital number, since it uses as much as digits as its factorization.

3551621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 900, while the sum is 23.

The square root of 3551621 is about 1884.5744877823. The cubic root of 3551621 is about 152.5722456219.

The spelling of 3551621 in words is "three million, five hundred fifty-one thousand, six hundred twenty-one".