1621166605 has 8 divisors (see below), whose sum is σ = 1945624032. Its totient is φ = 1296783888.

The previous prime is 1621166593. The next prime is 1621166623. The reversal of 1621166605 is 5066611261.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1621166605 - 2⁹ = 1621166093 is a prime.

It is a super-2 number, since 2×1621166605² = 5256362322334452050, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 56802 + ... + 80428.

It is an arithmetic number, because the mean of its divisors is an integer number (243203004).

Almost surely, 2^1621166605 is an apocalyptic number.

It is an amenable number.

1621166605 is a deficient number, since it is larger than the sum of its proper divisors (324457427).

1621166605 is a wasteful number, since it uses less digits than its factorization.

1621166605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37355.

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 1621166605 is about 40263.7132539958. The cubic root of 1621166605 is about 1174.7421447152.

Adding to 1621166605 its reverse (5066611261), we get a palindrome (6687777866).

The spelling of 1621166605 in words is "one billion, six hundred twenty-one million, one hundred sixty-six thousand, six hundred five".