21920782 has 16 divisors (see below), whose sum is σ = 36554112. Its totient is φ = 9790560.

The previous prime is 21920749. The next prime is 21920791. The reversal of 21920782 is 28702912.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a congruent number.

It is an unprimeable number.

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, 12793 + ... + 14404.

It is an arithmetic number, because the mean of its divisors is an integer number (2284632).

Almost surely, 2^21920782 is an apocalyptic number.

21920782 is a deficient number, since it is larger than the sum of its proper divisors (14633330).

21920782 is a wasteful number, since it uses less digits than its factorization.

21920782 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27243.

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 21920782 is about 4681.9634770041. The cubic root of 21920782 is about 279.8672074400.

The spelling of 21920782 in words is "twenty-one million, nine hundred twenty thousand, seven hundred eighty-two".