20721034 has 8 divisors (see below), whose sum is σ = 31100868. Its totient is φ = 10354080.

The previous prime is 20721013. The next prime is 20721037. The reversal of 20721034 is 43012702.

It can be written as a sum of positive squares in 2 ways, for example, as 20657025 + 64009 = 4545^2 + 253^2 .

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

It is a super-2 number, since 2×20721034² = 858722500058312, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20721037) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4734 + ... + 7990.

Almost surely, 2^20721034 is an apocalyptic number.

20721034 is a deficient number, since it is larger than the sum of its proper divisors (10379834).

20721034 is a wasteful number, since it uses less digits than its factorization.

20721034 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6440.

The product of its (nonzero) digits is 336, while the sum is 19.

The square root of 20721034 is about 4552.0362476588. The cubic root of 20721034 is about 274.6653074235.

Adding to 20721034 its reverse (43012702), we get a palindrome (63733736).

The spelling of 20721034 in words is "twenty million, seven hundred twenty-one thousand, thirty-four".