37221781 has 2 divisors, whose sum is σ = 37221782. Its totient is φ = 37221780.

The previous prime is 37221763. The next prime is 37221827. The reversal of 37221781 is 18712273.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 34035556 + 3186225 = 5834^2 + 1785^2 .

It is an emirp because it is prime and its reverse (18712273) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 37221781 - 2⁹ = 37221269 is a prime.

It is a super-2 number, since 2×37221781² = 2770921961623922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (37221581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 18610890 + 18610891.

It is an arithmetic number, because the mean of its divisors is an integer number (18610891).

Almost surely, 2^37221781 is an apocalyptic number.

It is an amenable number.

37221781 is a deficient number, since it is larger than the sum of its proper divisors (1).

37221781 is an equidigital number, since it uses as much as digits as its factorization.

37221781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4704, while the sum is 31.

The square root of 37221781 is about 6100.9655793161. The cubic root of 37221781 is about 333.8866462485.

The spelling of 37221781 in words is "thirty-seven million, two hundred twenty-one thousand, seven hundred eighty-one".