20686942 has 4 divisors (see below), whose sum is σ = 31030416. Its totient is φ = 10343470.

The previous prime is 20686937. The next prime is 20686949. The reversal of 20686942 is 24968602.

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

It is a super-2 number, since 2×20686942² = 855899138622728, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20686949) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5171734 + ... + 5171737.

It is an arithmetic number, because the mean of its divisors is an integer number (7757604).

Almost surely, 2^20686942 is an apocalyptic number.

20686942 is a deficient number, since it is larger than the sum of its proper divisors (10343474).

20686942 is a wasteful number, since it uses less digits than its factorization.

20686942 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10343473.

The product of its (nonzero) digits is 41472, while the sum is 37.

The square root of 20686942 is about 4548.2900083438. The cubic root of 20686942 is about 274.5145905275.

The spelling of 20686942 in words is "twenty million, six hundred eighty-six thousand, nine hundred forty-two".