21662464506451 has 4 divisors (see below), whose sum is σ = 21664403687304. Its totient is φ = 21660525325600.

The previous prime is 21662464506407. The next prime is 21662464506469. The reversal of 21662464506451 is 15460546426612.

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 21662464506451 - 2¹⁹ = 21662463982163 is a prime.

It is a super-3 number, since 3×21662464506451³ (a number of 41 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21662464506751) 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, 969573670 + ... + 969596011.

It is an arithmetic number, because the mean of its divisors is an integer number (5416100921826).

Almost surely, 2^{21662464506451} is an apocalyptic number.

21662464506451 is a deficient number, since it is larger than the sum of its proper divisors (1939180853).

21662464506451 is a wasteful number, since it uses less digits than its factorization.

21662464506451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1939180852.

The product of its (nonzero) digits is 8294400, while the sum is 52.

The spelling of 21662464506451 in words is "twenty-one trillion, six hundred sixty-two billion, four hundred sixty-four million, five hundred six thousand, four hundred fifty-one".