20121534 has 40 divisors (see below), whose sum is σ = 46652760. Its totient is φ = 6474384.

The previous prime is 20121533. The next prime is 20121539. The reversal of 20121534 is 43512102.

It is a super-2 number, since 2×20121534² = 809752261026312, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20121533) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 2557 + ... + 6839.

It is an arithmetic number, because the mean of its divisors is an integer number (1166319).

Almost surely, 2^20121534 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20121534, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23326380).

20121534 is an abundant number, since it is smaller than the sum of its proper divisors (26531226).

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

20121534 is a wasteful number, since it uses less digits than its factorization.

20121534 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4326 (or 4317 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 20121534 is about 4485.7032893405. The cubic root of 20121534 is about 271.9904750846.

Adding to 20121534 its reverse (43512102), we get a palindrome (63633636).

The spelling of 20121534 in words is "twenty million, one hundred twenty-one thousand, five hundred thirty-four".