20626978 has 4 divisors (see below), whose sum is σ = 30940470. Its totient is φ = 10313488.

The previous prime is 20626973. The next prime is 20626981. The reversal of 20626978 is 87962602.

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

It can be written as a sum of positive squares in only one way, i.e., 19864849 + 762129 = 4457^2 + 873^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 20626978.

It is not an unprimeable number, because it can be changed into a prime (20626973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5156743 + ... + 5156746.

Almost surely, 2^20626978 is an apocalyptic number.

20626978 is a deficient number, since it is larger than the sum of its proper divisors (10313492).

20626978 is a wasteful number, since it uses less digits than its factorization.

20626978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10313491.

The product of its (nonzero) digits is 72576, while the sum is 40.

The square root of 20626978 is about 4541.6932965580. The cubic root of 20626978 is about 274.2490941675.

The spelling of 20626978 in words is "twenty million, six hundred twenty-six thousand, nine hundred seventy-eight".