20551971 has 16 divisors (see below), whose sum is σ = 30146688. Its totient is φ = 12453320.

The previous prime is 20551961. The next prime is 20551987. The reversal of 20551971 is 17915502.

It is not a de Polignac number, because 20551971 - 2⁶ = 20551907 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20551931) 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, 1420 + ... + 6566.

It is an arithmetic number, because the mean of its divisors is an integer number (1884168).

Almost surely, 2^20551971 is an apocalyptic number.

20551971 is a deficient number, since it is larger than the sum of its proper divisors (9594717).

20551971 is an equidigital number, since it uses as much as digits as its factorization.

20551971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5183 (or 5161 counting only the distinct ones).

The product of its (nonzero) digits is 3150, while the sum is 30.

The square root of 20551971 is about 4533.4281730276. The cubic root of 20551971 is about 273.9162681262.

The spelling of 20551971 in words is "twenty million, five hundred fifty-one thousand, nine hundred seventy-one".