21961541 has 8 divisors (see below), whose sum is σ = 25348224. Its totient is φ = 18637200.

The previous prime is 21961531. The next prime is 21961543. The reversal of 21961541 is 14516912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21961541 - 2¹⁸ = 21699397 is a prime.

It is a super-3 number, since 3×21961541³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21961543) 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 7 ways as a sum of consecutive naturals, for example, 14825 + ... + 16238.

It is an arithmetic number, because the mean of its divisors is an integer number (3168528).

Almost surely, 2^21961541 is an apocalyptic number.

It is an amenable number.

21961541 is a deficient number, since it is larger than the sum of its proper divisors (3386683).

21961541 is a wasteful number, since it uses less digits than its factorization.

21961541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31171.

The product of its digits is 2160, while the sum is 29.

The square root of 21961541 is about 4686.3142233529. The cubic root of 21961541 is about 280.0405596006.

The spelling of 21961541 in words is "twenty-one million, nine hundred sixty-one thousand, five hundred forty-one".