20401557 has 8 divisors (see below), whose sum is σ = 29675040. Its totient is φ = 12364560.

The previous prime is 20401553. The next prime is 20401561. The reversal of 20401557 is 75510402.

It is an interprime number because it is at equal distance from previous prime (20401553) and next prime (20401561).

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

It is not a de Polignac number, because 20401557 - 2² = 20401553 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20401553) 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, 309082 + ... + 309147.

It is an arithmetic number, because the mean of its divisors is an integer number (3709380).

Almost surely, 2^20401557 is an apocalyptic number.

It is an amenable number.

20401557 is a deficient number, since it is larger than the sum of its proper divisors (9273483).

20401557 is a wasteful number, since it uses less digits than its factorization.

20401557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 618243.

The product of its (nonzero) digits is 1400, while the sum is 24.

The square root of 20401557 is about 4516.8082757629. The cubic root of 20401557 is about 273.2463929655.

Adding to 20401557 its reverse (75510402), we get a palindrome (95911959).

The spelling of 20401557 in words is "twenty million, four hundred one thousand, five hundred fifty-seven".