1901197649 has 4 divisors (see below), whose sum is σ = 2047443636. Its totient is φ = 1754951664.

The previous prime is 1901197633. The next prime is 1901197681. The reversal of 1901197649 is 9467911091.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9467911091 = 331 ⋅28603961.

It can be written as a sum of positive squares in 2 ways, for example, as 395214400 + 1505983249 = 19880^2 + 38807^2 .

It is a cyclic number.

It is not a de Polignac number, because 1901197649 - 2⁴ = 1901197633 is a prime.

It is a super-2 number, since 2×1901197649² = 7229105001126254402, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1901197699) 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, 73122974 + ... + 73122999.

It is an arithmetic number, because the mean of its divisors is an integer number (511860909).

Almost surely, 2^1901197649 is an apocalyptic number.

It is an amenable number.

1901197649 is a deficient number, since it is larger than the sum of its proper divisors (146245987).

1901197649 is a wasteful number, since it uses less digits than its factorization.

1901197649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146245986.

The product of its (nonzero) digits is 122472, while the sum is 47.

The square root of 1901197649 is about 43602.7252473971. The cubic root of 1901197649 is about 1238.8225140810.

The spelling of 1901197649 in words is "one billion, nine hundred one million, one hundred ninety-seven thousand, six hundred forty-nine".