20891937 has 16 divisors (see below), whose sum is σ = 31097088. Its totient is φ = 12366480.

The previous prime is 20891933. The next prime is 20891947. The reversal of 20891937 is 73919802.

It is not a de Polignac number, because 20891937 - 2² = 20891933 is a prime.

It is a super-2 number, since 2×20891937² = 872946063223938, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20891895 and 20891904.

It is not an unprimeable number, because it can be changed into a prime (20891933) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5943 + ... + 8780.

It is an arithmetic number, because the mean of its divisors is an integer number (1943568).

Almost surely, 2^20891937 is an apocalyptic number.

It is an amenable number.

20891937 is a deficient number, since it is larger than the sum of its proper divisors (10205151).

20891937 is a wasteful number, since it uses less digits than its factorization.

20891937 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14780.

The product of its (nonzero) digits is 27216, while the sum is 39.

The square root of 20891937 is about 4570.7698476296. The cubic root of 20891937 is about 275.4183692548.

The spelling of 20891937 in words is "twenty million, eight hundred ninety-one thousand, nine hundred thirty-seven".