20401669 has 4 divisors (see below), whose sum is σ = 20747520. Its totient is φ = 20055820.

The previous prime is 20401663. The next prime is 20401691. The reversal of 20401669 is 96610402.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20401669 is a prime.

It is a super-2 number, since 2×20401669² = 832456195971122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20401663) 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, 172837 + ... + 172954.

It is an arithmetic number, because the mean of its divisors is an integer number (5186880).

Almost surely, 2^20401669 is an apocalyptic number.

It is an amenable number.

20401669 is a deficient number, since it is larger than the sum of its proper divisors (345851).

20401669 is an equidigital number, since it uses as much as digits as its factorization.

20401669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 345850.

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 20401669 is about 4516.8206738811. The cubic root of 20401669 is about 273.2468929851.

The spelling of 20401669 in words is "twenty million, four hundred one thousand, six hundred sixty-nine".