21356734 has 16 divisors (see below), whose sum is σ = 37114848. Its totient is φ = 9027072.

The previous prime is 21356723. The next prime is 21356759. The reversal of 21356734 is 43765312.

It is a super-2 number, since 2×21356734² = 912220174293512, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21356696 and 21356705.

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, 9427 + ... + 11470.

It is an arithmetic number, because the mean of its divisors is an integer number (2319678).

Almost surely, 2^21356734 is an apocalyptic number.

21356734 is a deficient number, since it is larger than the sum of its proper divisors (15758114).

21356734 is a wasteful number, since it uses less digits than its factorization.

21356734 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20979.

The product of its digits is 15120, while the sum is 31.

The square root of 21356734 is about 4621.3346557028. The cubic root of 21356734 is about 277.4458796602.

The spelling of 21356734 in words is "twenty-one million, three hundred fifty-six thousand, seven hundred thirty-four".