20571397 has 16 divisors (see below), whose sum is σ = 25748352. Its totient is φ = 15966720.

The previous prime is 20571391. The next prime is 20571401. The reversal of 20571397 is 79317502.

It is not a de Polignac number, because 20571397 - 2³ = 20571389 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20571391) 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, 33033 + ... + 33649.

It is an arithmetic number, because the mean of its divisors is an integer number (1609272).

Almost surely, 2^20571397 is an apocalyptic number.

It is an amenable number.

20571397 is a deficient number, since it is larger than the sum of its proper divisors (5176955).

20571397 is a wasteful number, since it uses less digits than its factorization.

20571397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1068.

The product of its (nonzero) digits is 13230, while the sum is 34.

The square root of 20571397 is about 4535.5701956865. The cubic root of 20571397 is about 274.0025440650.

Adding to 20571397 its reverse (79317502), we get a palindrome (99888899).

The spelling of 20571397 in words is "twenty million, five hundred seventy-one thousand, three hundred ninety-seven".