20961897 has 12 divisors (see below), whose sum is σ = 30528336. Its totient is φ = 12688240.

The previous prime is 20961887. The next prime is 20961907. The reversal of 20961897 is 79816902.

It is an interprime number because it is at equal distance from previous prime (20961887) and next prime (20961907).

It is not a de Polignac number, because 20961897 - 2⁴ = 20961881 is a prime.

It is a super-2 number, since 2×20961897² = 878802251677218, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20961817) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 25903 + ... + 26699.

It is an arithmetic number, because the mean of its divisors is an integer number (2544028).

Almost surely, 2^20961897 is an apocalyptic number.

It is an amenable number.

20961897 is a deficient number, since it is larger than the sum of its proper divisors (9566439).

20961897 is an frugal number, since it uses more digits than its factorization.

20961897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1608 (or 811 counting only the distinct ones).

The product of its (nonzero) digits is 54432, while the sum is 42.

The square root of 20961897 is about 4578.4164292908. The cubic root of 20961897 is about 275.7254542546.

It can be divided in two parts, 2096 and 1897, that added together give a palindrome (3993).

The spelling of 20961897 in words is "twenty million, nine hundred sixty-one thousand, eight hundred ninety-seven".