20961057 has 16 divisors (see below), whose sum is σ = 30242240. Its totient is φ = 12837312.

The previous prime is 20961043. The next prime is 20961071. The reversal of 20961057 is 75016902.

It is an interprime number because it is at equal distance from previous prime (20961043) and next prime (20961071).

It is not a de Polignac number, because 20961057 - 2⁴ = 20961041 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20961557) 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, 7758 + ... + 10104.

It is an arithmetic number, because the mean of its divisors is an integer number (1890140).

Almost surely, 2^20961057 is an apocalyptic number.

It is an amenable number.

20961057 is a deficient number, since it is larger than the sum of its proper divisors (9281183).

20961057 is a wasteful number, since it uses less digits than its factorization.

20961057 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2592.

The product of its (nonzero) digits is 3780, while the sum is 30.

The square root of 20961057 is about 4578.3246935970. The cubic root of 20961057 is about 275.7217711834.

Adding to 20961057 its reverse (75016902), we get a palindrome (95977959).

The spelling of 20961057 in words is "twenty million, nine hundred sixty-one thousand, fifty-seven".