1900020401 has 4 divisors (see below), whose sum is σ = 1946362404. Its totient is φ = 1853678400.

The previous prime is 1900020391. The next prime is 1900020427. The reversal of 1900020401 is 1040200091.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1040200091 = 7 ⋅148600013.

It can be written as a sum of positive squares in 2 ways, for example, as 992565025 + 907455376 = 31505^2 + 30124^2 .

It is a cyclic number.

It is not a de Polignac number, because 1900020401 - 2¹⁴ = 1900004017 is a prime.

It is a super-2 number, since 2×1900020401² = 7220155048432401602, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1900020401.

It is not an unprimeable number, because it can be changed into a prime (1900020461) 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, 23170940 + ... + 23171021.

It is an arithmetic number, because the mean of its divisors is an integer number (486590601).

Almost surely, 2^1900020401 is an apocalyptic number.

It is an amenable number.

1900020401 is a deficient number, since it is larger than the sum of its proper divisors (46342003).

1900020401 is an equidigital number, since it uses as much as digits as its factorization.

1900020401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46342002.

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 1900020401 is about 43589.2234502979. The cubic root of 1900020401 is about 1238.5667625810.

Adding to 1900020401 its reverse (1040200091), we get a palindrome (2940220492).

The spelling of 1900020401 in words is "one billion, nine hundred million, twenty thousand, four hundred one".