21620742 has 64 divisors (see below), whose sum is σ = 51480576. Its totient is φ = 5967360.

The previous prime is 21620737. The next prime is 21620749. The reversal of 21620742 is 24702612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21620749) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 96843 + ... + 97065.

It is an arithmetic number, because the mean of its divisors is an integer number (804384).

Almost surely, 2^21620742 is an apocalyptic number.

21620742 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 21620742, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25740288).

21620742 is an abundant number, since it is smaller than the sum of its proper divisors (29859834).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21620742 is a wasteful number, since it uses less digits than its factorization.

21620742 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 365.

The product of its (nonzero) digits is 1344, while the sum is 24.

The square root of 21620742 is about 4649.8109638995. The cubic root of 21620742 is about 278.5844457898.

The spelling of 21620742 in words is "twenty-one million, six hundred twenty thousand, seven hundred forty-two".