611901981 has 12 divisors (see below), whose sum is σ = 889713760. Its totient is φ = 405232200.

The previous prime is 611901949. The next prime is 611901991. The reversal of 611901981 is 189109116.

It is not a de Polignac number, because 611901981 - 2⁵ = 611901949 is a prime.

It is a super-2 number, since 2×611901981² = 748848068703448722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (611901991) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 223771 + ... + 226488.

Almost surely, 2^611901981 is an apocalyptic number.

It is an amenable number.

611901981 is a deficient number, since it is larger than the sum of its proper divisors (277811779).

611901981 is a wasteful number, since it uses less digits than its factorization.

611901981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 450416 (or 450413 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 36.

The square root of 611901981 is about 24736.6525827566. The cubic root of 611901981 is about 848.9731456917.

The spelling of 611901981 in words is "six hundred eleven million, nine hundred one thousand, nine hundred eighty-one".