106521409 has 4 divisors (see below), whose sum is σ = 109400404. Its totient is φ = 103642416.

The previous prime is 106521347. The next prime is 106521461. The reversal of 106521409 is 904125601.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 904125601 = 457 ⋅1978393.

It can be written as a sum of positive squares in 2 ways, for example, as 65561409 + 40960000 = 8097^2 + 6400^2 .

It is a cyclic number.

It is not a de Polignac number, because 106521409 - 2⁷ = 106521281 is a prime.

It is a super-2 number, since 2×106521409² = 22693621150690562, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (106521469) 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, 1439442 + ... + 1439515.

It is an arithmetic number, because the mean of its divisors is an integer number (27350101).

Almost surely, 2^106521409 is an apocalyptic number.

It is an amenable number.

106521409 is a deficient number, since it is larger than the sum of its proper divisors (2878995).

106521409 is an equidigital number, since it uses as much as digits as its factorization.

106521409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2878994.

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 106521409 is about 10320.9209375908. The cubic root of 106521409 is about 474.0370652945.

The spelling of 106521409 in words is "one hundred six million, five hundred twenty-one thousand, four hundred nine".