1894212721 has 8 divisors (see below), whose sum is σ = 1925237160. Its totient is φ = 1863404928.

The previous prime is 1894212703. The next prime is 1894212757. The reversal of 1894212721 is 1272124981.

It can be written as a sum of positive squares in 4 ways, for example, as 209931121 + 1684281600 = 14489^2 + 41040^2 .

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 1894212721 - 2⁵ = 1894212689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1894212781) 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, 36486 + ... + 71551.

It is an arithmetic number, because the mean of its divisors is an integer number (240654645).

Almost surely, 2^1894212721 is an apocalyptic number.

It is an amenable number.

1894212721 is a deficient number, since it is larger than the sum of its proper divisors (31024439).

1894212721 is a wasteful number, since it uses less digits than its factorization.

1894212721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108323.

The product of its digits is 16128, while the sum is 37.

The square root of 1894212721 is about 43522.5541644789. The cubic root of 1894212721 is about 1237.3035233561.

The spelling of 1894212721 in words is "one billion, eight hundred ninety-four million, two hundred twelve thousand, seven hundred twenty-one".