21961542 has 16 divisors (see below), whose sum is σ = 44051760. Its totient is φ = 7299072.

The previous prime is 21961531. The next prime is 21961543. The reversal of 21961542 is 24516912.

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, 3067 + ... + 7302.

It is an arithmetic number, because the mean of its divisors is an integer number (2753235).

Almost surely, 2^21961542 is an apocalyptic number.

21961542 is an abundant number, since it is smaller than the sum of its proper divisors (22090218).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21961542 is a wasteful number, since it uses less digits than its factorization.

21961542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10727.

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

The square root of 21961542 is about 4686.3143300466. The cubic root of 21961542 is about 280.0405638511.

The spelling of 21961542 in words is "twenty-one million, nine hundred sixty-one thousand, five hundred forty-two".