21954261 has 16 divisors (see below), whose sum is σ = 33519744. Its totient is φ = 12520704.

The previous prime is 21954241. The next prime is 21954263. The reversal of 21954261 is 16245912.

It is not a de Polignac number, because 21954261 - 2²² = 17759957 is a prime.

It is a super-2 number, since 2×21954261² = 963979152112242, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21954263) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19465 + ... + 20561.

It is an arithmetic number, because the mean of its divisors is an integer number (2094984).

Almost surely, 2^21954261 is an apocalyptic number.

21954261 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21954261 is a deficient number, since it is larger than the sum of its proper divisors (11565483).

21954261 is a wasteful number, since it uses less digits than its factorization.

21954261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2060.

The product of its digits is 4320, while the sum is 30.

The square root of 21954261 is about 4685.5374291537. The cubic root of 21954261 is about 280.0096127652.

The spelling of 21954261 in words is "twenty-one million, nine hundred fifty-four thousand, two hundred sixty-one".