21820654 has 4 divisors (see below), whose sum is σ = 32730984. Its totient is φ = 10910326.

The previous prime is 21820633. The next prime is 21820661. The reversal of 21820654 is 45602812.

It is a semiprime because it is the product of two primes.

It is a super-2 number, since 2×21820654² = 952281881975432, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5455162 + ... + 5455165.

It is an arithmetic number, because the mean of its divisors is an integer number (8182746).

Almost surely, 2^21820654 is an apocalyptic number.

21820654 is a deficient number, since it is larger than the sum of its proper divisors (10910330).

21820654 is a wasteful number, since it uses less digits than its factorization.

21820654 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10910329.

The product of its (nonzero) digits is 3840, while the sum is 28.

The square root of 21820654 is about 4671.2582887269. The cubic root of 21820654 is about 279.4404386212.

The spelling of 21820654 in words is "twenty-one million, eight hundred twenty thousand, six hundred fifty-four".