37781641 has 2 divisors, whose sum is σ = 37781642. Its totient is φ = 37781640.

The previous prime is 37781621. The next prime is 37781647. The reversal of 37781641 is 14618773.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 31125241 + 6656400 = 5579^2 + 2580^2 .

It is a cyclic number.

It is not a de Polignac number, because 37781641 - 2⁵ = 37781609 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 37781641.

It is not a weakly prime, because it can be changed into another prime (37781647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 18890820 + 18890821.

It is an arithmetic number, because the mean of its divisors is an integer number (18890821).

Almost surely, 2^37781641 is an apocalyptic number.

37781641 is the 3888-th centered pentagonal number.

It is an amenable number.

37781641 is a deficient number, since it is larger than the sum of its proper divisors (1).

37781641 is an equidigital number, since it uses as much as digits as its factorization.

37781641 is an evil number, because the sum of its binary digits is even.

The product of its digits is 28224, while the sum is 37.

The square root of 37781641 is about 6146.6772324566. The cubic root of 37781641 is about 335.5523404651.

The spelling of 37781641 in words is "thirty-seven million, seven hundred eighty-one thousand, six hundred forty-one".