1642400221 has 16 divisors (see below), whose sum is σ = 2050139520. Its totient is φ = 1278247680.

The previous prime is 1642400219. The next prime is 1642400257. The reversal of 1642400221 is 1220042461.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 1642400221 - 2¹ = 1642400219 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1642400192 and 1642400201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1642400281) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 53545 + ... + 78433.

It is an arithmetic number, because the mean of its divisors is an integer number (128133720).

Almost surely, 2^1642400221 is an apocalyptic number.

1642400221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1642400221 is a deficient number, since it is larger than the sum of its proper divisors (407739299).

1642400221 is a wasteful number, since it uses less digits than its factorization.

1642400221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25764.

The product of its (nonzero) digits is 768, while the sum is 22.

The square root of 1642400221 is about 40526.5372441318. The cubic root of 1642400221 is about 1179.8487359967.

Adding to 1642400221 its reverse (1220042461), we get a palindrome (2862442682).

The spelling of 1642400221 in words is "one billion, six hundred forty-two million, four hundred thousand, two hundred twenty-one".