20964961 has 16 divisors (see below), whose sum is σ = 23880960. Its totient is φ = 18282240.

The previous prime is 20964947. The next prime is 20964967. The reversal of 20964961 is 16946902.

It is a 2-Lehmer number, since φ(20964961) divides (20964961-1)².

It is a cyclic number.

It is a Carmichael number.

It is not a de Polignac number, because 20964961 - 2¹⁷ = 20833889 is a prime.

It is a deceptive number, since it divides R_20964960.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20964961.

It is not an unprimeable number, because it can be changed into a prime (20964967) 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, 14491 + ... + 15871.

It is an arithmetic number, because the mean of its divisors is an integer number (1492560).

It is a Poulet number, since it divides 2^20964960-1.

Almost surely, 2^20964961 is an apocalyptic number.

It is an amenable number.

20964961 is a deficient number, since it is larger than the sum of its proper divisors (2915999).

20964961 is a wasteful number, since it uses less digits than its factorization.

20964961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1464.

The product of its (nonzero) digits is 23328, while the sum is 37.

The square root of 20964961 is about 4578.7510305759. The cubic root of 20964961 is about 275.7388878612.

The spelling of 20964961 in words is "twenty million, nine hundred sixty-four thousand, nine hundred sixty-one".