21637742 has 8 divisors (see below), whose sum is σ = 37093296. Its totient is φ = 9273312.

The previous prime is 21637739. The next prime is 21637807. The reversal of 21637742 is 24773612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 21637699 and 21637708.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 772763 + ... + 772790.

It is an arithmetic number, because the mean of its divisors is an integer number (4636662).

Almost surely, 2^21637742 is an apocalyptic number.

21637742 is a deficient number, since it is larger than the sum of its proper divisors (15455554).

21637742 is a wasteful number, since it uses less digits than its factorization.

21637742 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1545562.

The product of its digits is 14112, while the sum is 32.

The square root of 21637742 is about 4651.6386360077. The cubic root of 21637742 is about 278.6574419719.

The spelling of 21637742 in words is "twenty-one million, six hundred thirty-seven thousand, seven hundred forty-two".