20401491 has 8 divisors (see below), whose sum is σ = 29674944. Its totient is φ = 12364520.

The previous prime is 20401489. The next prime is 20401499. The reversal of 20401491 is 19410402.

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

It is a cyclic number.

It is not a de Polignac number, because 20401491 - 2¹ = 20401489 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20401499) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 309081 + ... + 309146.

It is an arithmetic number, because the mean of its divisors is an integer number (3709368).

Almost surely, 2^20401491 is an apocalyptic number.

20401491 is a deficient number, since it is larger than the sum of its proper divisors (9273453).

20401491 is a wasteful number, since it uses less digits than its factorization.

20401491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 618241.

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 20401491 is about 4516.8009697130. The cubic root of 20401491 is about 273.2460983101.

Adding to 20401491 its reverse (19410402), we get a palindrome (39811893).

The spelling of 20401491 in words is "twenty million, four hundred one thousand, four hundred ninety-one".