21662205151 has 4 divisors (see below), whose sum is σ = 21967306704. Its totient is φ = 21357103600.

The previous prime is 21662205091. The next prime is 21662205157. The reversal of 21662205151 is 15150226612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21662205151 - 2¹⁹ = 21661680863 is a prime.

It is a super-2 number, since 2×21662205151² (a number of 21 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21662205157) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 152550670 + ... + 152550811.

It is an arithmetic number, because the mean of its divisors is an integer number (5491826676).

Almost surely, 2^21662205151 is an apocalyptic number.

21662205151 is a deficient number, since it is larger than the sum of its proper divisors (305101553).

21662205151 is an equidigital number, since it uses as much as digits as its factorization.

21662205151 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 305101552.

The product of its (nonzero) digits is 7200, while the sum is 31.

The spelling of 21662205151 in words is "twenty-one billion, six hundred sixty-two million, two hundred five thousand, one hundred fifty-one".