21963081 has 16 divisors (see below), whose sum is σ = 33542144. Its totient is φ = 12522384.

The previous prime is 21963079. The next prime is 21963103. The reversal of 21963081 is 18036912.

It is not a de Polignac number, because 21963081 - 2¹ = 21963079 is a prime.

It is a super-2 number, since 2×21963081² = 964753854025122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21963001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11886 + ... + 13608.

It is an arithmetic number, because the mean of its divisors is an integer number (2096384).

Almost surely, 2^21963081 is an apocalyptic number.

21963081 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21963081 is a deficient number, since it is larger than the sum of its proper divisors (11579063).

21963081 is a wasteful number, since it uses less digits than its factorization.

21963081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2340.

The product of its (nonzero) digits is 2592, while the sum is 30.

The square root of 21963081 is about 4686.4785287036. The cubic root of 21963081 is about 280.0471051702.

Adding to 21963081 its reverse (18036912), we get a palindrome (39999993).

The spelling of 21963081 in words is "twenty-one million, nine hundred sixty-three thousand, eighty-one".