1990261 has 8 divisors (see below), whose sum is σ = 2449664. Its totient is φ = 1574640.

The previous prime is 1990253. The next prime is 1990273. The reversal of 1990261 is 1620991.

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

It is a 5-Lehmer number, since φ(1990261) divides (1990261-1)⁵.

It is a cyclic number.

It is not a de Polignac number, because 1990261 - 2³ = 1990253 is a prime.

It is a super-2 number, since 2×1990261² = 7922277696242, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1990211) 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, 10845 + ... + 11026.

It is an arithmetic number, because the mean of its divisors is an integer number (306208).

2^1990261 is an apocalyptic number.

It is an amenable number.

1990261 is a deficient number, since it is larger than the sum of its proper divisors (459403).

1990261 is a wasteful number, since it uses less digits than its factorization.

1990261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21891.

The product of its (nonzero) digits is 972, while the sum is 28.

The square root of 1990261 is about 1410.7661039308. The cubic root of 1990261 is about 125.7872659558.

The spelling of 1990261 in words is "one million, nine hundred ninety thousand, two hundred sixty-one".