21985834 has 16 divisors (see below), whose sum is σ = 35642880. Its totient is φ = 10110960.

The previous prime is 21985829. The next prime is 21985837. The reversal of 21985834 is 43858912.

It is not an unprimeable number, because it can be changed into a prime (21985837) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6727 + ... + 9445.

It is an arithmetic number, because the mean of its divisors is an integer number (2227680).

Almost surely, 2^21985834 is an apocalyptic number.

21985834 is a deficient number, since it is larger than the sum of its proper divisors (13657046).

21985834 is a wasteful number, since it uses less digits than its factorization.

21985834 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3045.

The product of its digits is 69120, while the sum is 40.

The square root of 21985834 is about 4688.9054159793. The cubic root of 21985834 is about 280.1437781990.

It can be divided in two parts, 219 and 85834, that multiplied together give a triangular number (18797646 = T₆₁₃₁).

The spelling of 21985834 in words is "twenty-one million, nine hundred eighty-five thousand, eight hundred thirty-four".