690971251 has 2 divisors, whose sum is σ = 690971252. Its totient is φ = 690971250.

The previous prime is 690971231. The next prime is 690971261. The reversal of 690971251 is 152179096.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 690971251 - 2¹³ = 690963059 is a prime.

It is not a weakly prime, because it can be changed into another prime (690971231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345485625 + 345485626.

It is an arithmetic number, because the mean of its divisors is an integer number (345485626).

Almost surely, 2^690971251 is an apocalyptic number.

690971251 is a deficient number, since it is larger than the sum of its proper divisors (1).

690971251 is an equidigital number, since it uses as much as digits as its factorization.

690971251 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34020, while the sum is 40.

The square root of 690971251 is about 26286.3320187507. The cubic root of 690971251 is about 884.0700120461.

The spelling of 690971251 in words is "six hundred ninety million, nine hundred seventy-one thousand, two hundred fifty-one".