20401836 has 144 divisors (see below), whose sum is σ = 63546336. Its totient is φ = 5031936.

The previous prime is 20401831. The next prime is 20401859. The reversal of 20401836 is 63810402.

It is a happy number.

20401836 is a modest number, since divided by 1836 gives 204 as remainder.

It is not an unprimeable number, because it can be changed into a prime (20401831) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 129870 + ... + 130026.

It is an arithmetic number, because the mean of its divisors is an integer number (441294).

Almost surely, 2^20401836 is an apocalyptic number.

20401836 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20401836, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31773168).

20401836 is an abundant number, since it is smaller than the sum of its proper divisors (43144500).

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

20401836 is a wasteful number, since it uses less digits than its factorization.

20401836 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 208 (or 199 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 20401836 is about 4516.8391602978. The cubic root of 20401836 is about 273.2476385468.

It can be divided in two parts, 20 and 401836, that added together give a triangular number (401856 = T₈₉₆).

The spelling of 20401836 in words is "twenty million, four hundred one thousand, eight hundred thirty-six".