20621965 has 32 divisors (see below), whose sum is σ = 30998016. Its totient is φ = 12821760.

The previous prime is 20621963. The next prime is 20621971. The reversal of 20621965 is 56912602.

It is not a de Polignac number, because 20621965 - 2¹ = 20621963 is a prime.

It is a super-2 number, since 2×20621965² = 850530880922450, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20621963) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 27384 + ... + 28126.

It is an arithmetic number, because the mean of its divisors is an integer number (968688).

Almost surely, 2^20621965 is an apocalyptic number.

It is an amenable number.

20621965 is a deficient number, since it is larger than the sum of its proper divisors (10376051).

20621965 is a wasteful number, since it uses less digits than its factorization.

20621965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 829.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 20621965 is about 4541.1413763502. The cubic root of 20621965 is about 274.2268753352.

The spelling of 20621965 in words is "twenty million, six hundred twenty-one thousand, nine hundred sixty-five".