20401236 has 18 divisors (see below), whose sum is σ = 51569882. Its totient is φ = 6800400.

The previous prime is 20401223. The next prime is 20401273. The reversal of 20401236 is 63210402.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 17139600 + 3261636 = 4140^2 + 1806^2 .

It is a tau number, because it is divible by the number of its divisors (18).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 283315 + ... + 283386.

Almost surely, 2^20401236 is an apocalyptic number.

It is an amenable number.

20401236 is an abundant number, since it is smaller than the sum of its proper divisors (31168646).

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

20401236 is a wasteful number, since it uses less digits than its factorization.

20401236 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 566711 (or 566706 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 20401236 is about 4516.7727416818. The cubic root of 20401236 is about 273.2449598632.

Adding to 20401236 its reverse (63210402), we get a palindrome (83611638).

The spelling of 20401236 in words is "twenty million, four hundred one thousand, two hundred thirty-six".