21739630 has 32 divisors (see below), whose sum is σ = 42910560. Its totient is φ = 7864320.

The previous prime is 21739603. The next prime is 21739637. The reversal of 21739630 is 3693712.

21739630 = T₃₃₀ + T₃₃₁ + ... + T₅₄₉.

It is a super-2 number, since 2×21739630² = 945223025073800, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21739592 and 21739601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21739637) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27886 + ... + 28654.

It is an arithmetic number, because the mean of its divisors is an integer number (1340955).

Almost surely, 2^21739630 is an apocalyptic number.

21739630 is a deficient number, since it is larger than the sum of its proper divisors (21170930).

21739630 is a wasteful number, since it uses less digits than its factorization.

21739630 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1044.

The product of its (nonzero) digits is 6804, while the sum is 31.

The square root of 21739630 is about 4662.5776132950. The cubic root of 21739630 is about 279.0941388282.

The spelling of 21739630 in words is "twenty-one million, seven hundred thirty-nine thousand, six hundred thirty".