20345971 has 4 divisors (see below), whose sum is σ = 20778912. Its totient is φ = 19913032.

The previous prime is 20345953. The next prime is 20345987. The reversal of 20345971 is 17954302.

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

It is a cyclic number.

It is not a de Polignac number, because 20345971 - 2¹⁵ = 20313203 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20345921) 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, 216400 + ... + 216493.

It is an arithmetic number, because the mean of its divisors is an integer number (5194728).

Almost surely, 2^20345971 is an apocalyptic number.

20345971 is a deficient number, since it is larger than the sum of its proper divisors (432941).

20345971 is an equidigital number, since it uses as much as digits as its factorization.

20345971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 432940.

The product of its (nonzero) digits is 7560, while the sum is 31.

The square root of 20345971 is about 4510.6508399565. The cubic root of 20345971 is about 272.9980052362.

It can be divided in two parts, 20345 and 971, that added together give a square (21316 = 146²).

The spelling of 20345971 in words is "twenty million, three hundred forty-five thousand, nine hundred seventy-one".