20861471 has 4 divisors (see below), whose sum is σ = 20876352. Its totient is φ = 20846592.

The previous prime is 20861459. The next prime is 20861509. The reversal of 20861471 is 17416802.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20861471 is a prime.

It is a super-3 number, since 3×20861471³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20861441) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5090 + ... + 8223.

It is an arithmetic number, because the mean of its divisors is an integer number (5219088).

Almost surely, 2^20861471 is an apocalyptic number.

20861471 is a deficient number, since it is larger than the sum of its proper divisors (14881).

20861471 is a wasteful number, since it uses less digits than its factorization.

20861471 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14880.

The product of its (nonzero) digits is 2688, while the sum is 29.

The square root of 20861471 is about 4567.4359327745. The cubic root of 20861471 is about 275.2844263839.

The spelling of 20861471 in words is "twenty million, eight hundred sixty-one thousand, four hundred seventy-one".