20621871 has 20 divisors (see below), whose sum is σ = 31871400. Its totient is φ = 13272336.

The previous prime is 20621827. The next prime is 20621891. The reversal of 20621871 is 17812602.

It is not a de Polignac number, because 20621871 - 2⁶ = 20621807 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20621891) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 2041 + ... + 6738.

It is an arithmetic number, because the mean of its divisors is an integer number (1593570).

Almost surely, 2^20621871 is an apocalyptic number.

20621871 is a deficient number, since it is larger than the sum of its proper divisors (11249529).

20621871 is an equidigital number, since it uses as much as digits as its factorization.

20621871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8820 (or 8811 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 27.

The square root of 20621871 is about 4541.1310265175. The cubic root of 20621871 is about 274.2264586700.

The spelling of 20621871 in words is "twenty million, six hundred twenty-one thousand, eight hundred seventy-one".