21742006 has 24 divisors (see below), whose sum is σ = 38610432. Its totient is φ = 9121200.

The previous prime is 21742003. The next prime is 21742009. The reversal of 21742006 is 60024712.

It is an interprime number because it is at equal distance from previous prime (21742003) and next prime (21742009).

It is a super-3 number, since 3×21742006³ (a number of 23 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21742001) 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 11 ways as a sum of consecutive naturals, for example, 310 + ... + 6601.

It is an arithmetic number, because the mean of its divisors is an integer number (1608768).

Almost surely, 2^21742006 is an apocalyptic number.

21742006 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21742006 is a deficient number, since it is larger than the sum of its proper divisors (16868426).

21742006 is a wasteful number, since it uses less digits than its factorization.

21742006 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6948 (or 6937 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 22.

The square root of 21742006 is about 4662.8324010198. The cubic root of 21742006 is about 279.1043061818.

Adding to 21742006 its reverse (60024712), we get a palindrome (81766718).

The spelling of 21742006 in words is "twenty-one million, seven hundred forty-two thousand, six".