20639954 has 4 divisors (see below), whose sum is σ = 30959934. Its totient is φ = 10319976.

The previous prime is 20639939. The next prime is 20639959. The reversal of 20639954 is 45993602.

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., 18879025 + 1760929 = 4345^2 + 1327^2 .

It is a super-2 number, since 2×20639954² = 852015402244232, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20639959) 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, 5159987 + ... + 5159990.

Almost surely, 2^20639954 is an apocalyptic number.

20639954 is a deficient number, since it is larger than the sum of its proper divisors (10319980).

20639954 is a wasteful number, since it uses less digits than its factorization.

20639954 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10319979.

The product of its (nonzero) digits is 58320, while the sum is 38.

The square root of 20639954 is about 4543.1216140447. The cubic root of 20639954 is about 274.3065902338.

The spelling of 20639954 in words is "twenty million, six hundred thirty-nine thousand, nine hundred fifty-four".