1621666011 has 16 divisors (see below), whose sum is σ = 2471724288. Its totient is φ = 926436000.

The previous prime is 1621665977. The next prime is 1621666027. The reversal of 1621666011 is 1106661261.

It is not a de Polignac number, because 1621666011 - 2¹⁰ = 1621664987 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1621666011.

It is not an unprimeable number, because it can be changed into a prime (1621661011) 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, 113836 + ... + 127286.

It is an arithmetic number, because the mean of its divisors is an integer number (154482768).

Almost surely, 2^1621666011 is an apocalyptic number.

1621666011 is a deficient number, since it is larger than the sum of its proper divisors (850058277).

1621666011 is a wasteful number, since it uses less digits than its factorization.

1621666011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19202.

The product of its (nonzero) digits is 2592, while the sum is 30.

The square root of 1621666011 is about 40269.9144647713. The cubic root of 1621666011 is about 1174.8627601292.

The spelling of 1621666011 in words is "one billion, six hundred twenty-one million, six hundred sixty-six thousand, eleven".