642622451 has 4 divisors (see below), whose sum is σ = 642673152. Its totient is φ = 642571752.

The previous prime is 642622441. The next prime is 642622469. The reversal of 642622451 is 154226246.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 154226246 = 2 ⋅77113123.

It is a cyclic number.

It is not a de Polignac number, because 642622451 - 2¹⁴ = 642606067 is a prime.

It is a super-2 number, since 2×642622451² = 825927229058494802, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (642622441) 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, 12665 + ... + 38021.

It is an arithmetic number, because the mean of its divisors is an integer number (160668288).

Almost surely, 2^642622451 is an apocalyptic number.

642622451 is a deficient number, since it is larger than the sum of its proper divisors (50701).

642622451 is a wasteful number, since it uses less digits than its factorization.

642622451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50700.

The product of its digits is 23040, while the sum is 32.

The square root of 642622451 is about 25349.9990335306. Note that the first 3 decimals coincide. The cubic root of 642622451 is about 862.9493343368.

Adding to 642622451 its reverse (154226246), we get a palindrome (796848697).

The spelling of 642622451 in words is "six hundred forty-two million, six hundred twenty-two thousand, four hundred fifty-one".