20661724 has 6 divisors (see below), whose sum is σ = 36158024. Its totient is φ = 10330860.

The previous prime is 20661703. The next prime is 20661727. The reversal of 20661724 is 42716602.

It is a junction number, because it is equal to n+sod(n) for n = 20661692 and 20661701.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20661727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2582712 + ... + 2582719.

Almost surely, 2^20661724 is an apocalyptic number.

It is an amenable number.

20661724 is a deficient number, since it is larger than the sum of its proper divisors (15496300).

20661724 is a wasteful number, since it uses less digits than its factorization.

20661724 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5165435 (or 5165433 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 28.

The square root of 20661724 is about 4545.5169122994. The cubic root of 20661724 is about 274.4029980094.

The spelling of 20661724 in words is "twenty million, six hundred sixty-one thousand, seven hundred twenty-four".